from the master himself... yeah, yeah, he's a tough read... he's often tangential, but there is only one WENDELL ODOM...
if you are not keeping up with his musings at his blog, if you have not put his link in your favorites, and if you are not using his books, abusing them, sleeping with them, shame on you...
his blog is here http://ccnaskills.wordpress.com/
he's posing an interesting STP dilemma/puzzle...
who's your daddy? Odom's your daddy...
network cisco ccna gns3 certification arteq
a network runs through it
Wednesday, November 30, 2011
ip classclap...
the difference between ip classless and no ip classless is in the ability to ascertain whether or not the default route can or will be used...
use this site here http://subnettingmadeeasy.blogspot.com/2009/06/ip-classless-versus-no-ip-classless.html for this and many more discussions about this subject we love to hate... and check out his many more articles and tutorials...
thanks chris...
it gets tedious that for certification purposes one is compelled to perform the operations normally performed by a router in ones head... like route summarization... a ccie friend of mine one day replied, when i boasted i could subnet in my head, "why not use a subnet calculator?"
yeah, why not, Cisco?
use this site here http://subnettingmadeeasy.blogspot.com/2009/06/ip-classless-versus-no-ip-classless.html for this and many more discussions about this subject we love to hate... and check out his many more articles and tutorials...
thanks chris...
it gets tedious that for certification purposes one is compelled to perform the operations normally performed by a router in ones head... like route summarization... a ccie friend of mine one day replied, when i boasted i could subnet in my head, "why not use a subnet calculator?"
yeah, why not, Cisco?
EIGRP | more...
EIGRP is IGRP on acid. EIGRP uses the same DV technology as IGRP; the distance information remains unchanged. Convergence has improved.
EIGRP uses DUAL (diffusing update algorithm) to be free of routing loops during route computation, allowing routers involved in topology changes to sync simultaneously. Routers not part of the topology change are not included.
Building blocks:
Neighbor discovery/recovery- discovery allows for dynamic learning of routers on attached networks (directly connected networks) Discovery includes reachability or non-reachability and operational quality (or inop). Hello packets achieve this.
RTP- guarantees ordered reliable delivery of packets to neighbors when necessary. In the event of multi-cast capability, individual packets will not be sent. Rather, a single multicast hello will be sent indicating the packet need not be acknowledged.
DUAL- keeps track of neighbor advertised routes. Distance (metric) allows DUAL to select loop free efficient paths. DUAL selects the feasible successors. The feasible successor is a neighbor router with least cost path, and determined by DUAL to be loop free. If there are no feasible successors, a recomputation occurs to determine a successor. This affects convergence time but is not CPU intensive.
Protocol Dependent Modules- for IP, IP-EIGRP informs DUAL of newly received information. IP-EIGRP also redistributes routes learned by other IP routing protocols.
EIGRP uses DUAL (diffusing update algorithm) to be free of routing loops during route computation, allowing routers involved in topology changes to sync simultaneously. Routers not part of the topology change are not included.
Building blocks:
Neighbor discovery/recovery- discovery allows for dynamic learning of routers on attached networks (directly connected networks) Discovery includes reachability or non-reachability and operational quality (or inop). Hello packets achieve this.
RTP- guarantees ordered reliable delivery of packets to neighbors when necessary. In the event of multi-cast capability, individual packets will not be sent. Rather, a single multicast hello will be sent indicating the packet need not be acknowledged.
DUAL- keeps track of neighbor advertised routes. Distance (metric) allows DUAL to select loop free efficient paths. DUAL selects the feasible successors. The feasible successor is a neighbor router with least cost path, and determined by DUAL to be loop free. If there are no feasible successors, a recomputation occurs to determine a successor. This affects convergence time but is not CPU intensive.
Protocol Dependent Modules- for IP, IP-EIGRP informs DUAL of newly received information. IP-EIGRP also redistributes routes learned by other IP routing protocols.
Sunday, November 27, 2011
spanning tree very pretty...
STP summary
1. all bridge
(switch ports) stabilize at forwarding or blocking. Forwarding ports are considered part of the
spanning tree.
2. one switch is
elected root, and its ports will all move to forwarding state.
3. each switch
receives hellos from the root, directly or through another switch. The port
that receives the least cost BPDU is placed in forwarding and becomes that
switch’s root port
4. for each
segment one switch forwards the BPDU with the lowest cost. That switch becomes that segment’s designated
bridge.
5. the other
interfaces are placed in blocking
6. the root sends
BPDU’s every 2 seconds. This time interval can be modified and will be noted in
the BPDU.
7. if max-age
elapses (20 seconds, default) and no BPDU, panic ensues and the spanning tree
changes.
8. forward delay
(default 15 seconds) is the time it takes for a port to transition through the
dumbass states to forwarding. (listening, 15 seconds, learning 15 seconds)
9. when a switch
goes into listening, it sends a TCN BPDU (topology change notification) through
the new path to the root. Other switches will refresh their tables with the new
entry.
10. spanning tree creates these delays to prevent
transitional loops because…
spanning tree, very pretty and the bpdu’s are sweet,
but the root of the poor spanning, is impossible to eat…
santa, please don't bring me a collision domain for xmas...
my switch kicked your collision domains ass while you were busy layering that OSI model...
spanning-tree song...
spanning-tree very pretty and the bpdu's are sweet,
but the root of the poor spanning, is impossible to eat,
Michael the network cat likes that song... reow
but the root of the poor spanning, is impossible to eat,
Michael the network cat likes that song... reow
STP elects a root bridge (switch) and puts all root bridge
interfaces into forwarding state
Each non root bridge (switch)
determines which of its ports has the least administrative cost (best) to the
root bridge and STP makes that port that switch’s root port.
The switch with the lowest (best)
cost to the root is put in forwarding
state.
The lowest cost switch on each
segment is the designated bridge (switch) and the interface on that switch is
called the designated port.
The
root bridge’s (switch) ports are always in forwarding state and the root switch
(bridge) is always the designated bridge on all connected segments.
The
non root bridge root port is always forwarding. This port receives the lowest
cost BPDU from the root.
Each
LAN’s designated port is always forwarding and the bridge forwarding the lowest
cost BPDU is the segment’s designated bridge (switch)
All other ports are blocking. No forwarding
frames, no receiving frames.
At first each switch claims to be root
by sending BPDU’s that contain:
The root bridge ID- a
combination switch priority and MAC address, lower number, higher priority
The cost to reach the root- again the lower,
the better
And it’s own bridge ID
can't we just call a root bridge a root switch instead...
can't we just call a root bridge a root switch instead...
please stop teaching and using csma/cd now...
God....
on a csma/cd Ethernet
a device with a frame to send listens for the Ethernet to be
not busy
the device sends the frame after not busy detected
the sender listens to ensure no collision has been detected
after a collision is detected, they each send a jamming
signal to ensure all stations
recognize the
collision
after jamming is complete each sender randomizes a timer and
waits
after timer expiration start step 1
half-duplex Ethernet
uses a loopback circuit to detect collisions. Full duplex uses two wire pairs
to avoid collisions altogether. Full duplex is good because it is collision
free with increased throughput
this is very exciting to my baby ears...
summarization redux...
are you sick of writing down all the bits then counting from left to right... me too...
look at the examples below and answer the multiple choice...
summarize 10.1.32.0 to 10.1.35.255?
a)10.1.32.0/23
b)10.1.32.0/22
c)10.1.32.0/21
d)10.1.32.0/20
summarize 172.168.12.0/24 to 172.168.13.0/24?
a)172.168.12.0/23
b)172.168.12.0/22
c)172.168.12.0/21
d)172.168.12.0/20
example 1
step 1: identify the octet where the action is. the action is where the numbers change
in the first example the numbers change in the third octet, and like wise in the second example
.32 to .35 (you don't have to write down all the numbers, just the beginning and end of the range)
and .12 to .13
step 2: the first 2 octets are the same 10.1 and 172.168. together they comprise 16 bits so 16 is our working number
step 3: write down the first number .32 in example 1 and the last number where the change occurred, .35
.32
0010 0000
.35
0010 0011
count up to, but not including where the bits change and add 16 + 6 = /22
16 is the working number, determined by the address where there are no changes and 6 is the last position in the octet before a change
example 2
summarize 172.168.12.0/24 to 172.168.13.0/24?
the change happens in the third octet
.12
0000 1100
.13
0000 1101
16 plus 7 = /23
Class of address does not matter... the working number is always determined by the octet where the change occurs...
not sure about you, but there are a lot less 1's and zero's to count with my method... go ahead and prove this wrong...
Saturday, November 26, 2011
TCP segment...
this shit gets old...
The TCP segment includes 12 fields:
1. Source port 2.
Destination port. These first two fields
identify the upper layer source and destination ports processed by TCP
services. 3. Sequence number usually
specifies the number assigned to the first byte of data in the current message.
It can also be used to identify an initial sequence number for a future
transmission. 4. Acknowledgement number,
contains the sequence number of the next
byte of data the sender expects to receive.
5. Data offset indicates the
number of 32 bit words in the TCP header.
6. Reserved-for future use. 7. Flags- carries control information, including
syn-ack bits for connection establishment, and FIN for connection
termination. 8. Window-specifies the size of the sender’s
receive window (buffer space available for incoming data) 9. Checksum-indicating header transmission
damage if applicable. 10. Urgent pointer- points to the first urgent
byte in the packet 11. Options-various
tcp options, and 12. Data, contains upper layer information.
Friday, November 25, 2011
DV, or routing 101...
just when you thought you were becoming proficient at routing, advanced concepts and the like, area id's and autonomous systems, ad infinitum, you suffer a setback with the likes of this:
a router has two primary functions:
path determination and packet forwarding
time to live (ttl) has a maximum value of 255, and has nothing to do with hop count
hop count refers to the number of routers a packet must pass through en route from source to destination
which of the above (path determination, packet forwarding) is hop count concerned with?
answer:
hop count determines distance and is placed in the routing table (path determination) while ttl determines how long a packet will be allowed to traverse the network before being discarded (packet forwarding)
easy, right?
see this link and curdle your brain http://www.ietf.org/rfc/rfc2453.txt
a router has two primary functions:
path determination and packet forwarding
time to live (ttl) has a maximum value of 255, and has nothing to do with hop count
hop count refers to the number of routers a packet must pass through en route from source to destination
which of the above (path determination, packet forwarding) is hop count concerned with?
answer:
hop count determines distance and is placed in the routing table (path determination) while ttl determines how long a packet will be allowed to traverse the network before being discarded (packet forwarding)
easy, right?
see this link and curdle your brain http://www.ietf.org/rfc/rfc2453.txt
Wednesday, November 23, 2011
Stinky Toilet Paper...
this is gonna hurt you more than me...
spanning-tree port states... arrrrrrrrrrrrrrgh
after initializing, a switchport always enters the blocking state
blocking:
the port dumps the frames received
dumps frames switched for forwarding from another switch
doesn't learn shit
receives bpdu's
listening:
the port dumps the frames received
dumps frames switched for forwarding from another switch
doesn't learn shit
receives bpdu's
learning:
the port dumps the frames received
dumps frames switched for forwarding from another switch
finally gets off its dead ass and learns addresses
receives bpdu's
forwarding:
receives and forwards frames
forwards frames switched from another port
learns addresses
receives bpdu's
disabled:
doesn't do shit
spanning-tree port states... arrrrrrrrrrrrrrgh
after initializing, a switchport always enters the blocking state
blocking:
the port dumps the frames received
dumps frames switched for forwarding from another switch
doesn't learn shit
receives bpdu's
listening:
the port dumps the frames received
dumps frames switched for forwarding from another switch
doesn't learn shit
receives bpdu's
learning:
the port dumps the frames received
dumps frames switched for forwarding from another switch
finally gets off its dead ass and learns addresses
receives bpdu's
forwarding:
receives and forwards frames
forwards frames switched from another port
learns addresses
receives bpdu's
disabled:
doesn't do shit
use begin before the end...
r2620_01#sh run | begin vty
line vty 0 4
exec-timeout 0 0
privilege level 15
password 7 07003B56470C4854
login
transport input telnet ssh
line vty 5 181
exec-timeout 0 0
privilege level 15
password 7 07003B56470C4854
login
transport input telnet ssh
!
!
end
r2620_01#sh run | begin ssh
transport input telnet ssh
line vty 5 181
exec-timeout 0 0
privilege level 15
password 7 07003B56470C4854
login
transport input telnet ssh
!
!
end
you get the idea...
line vty 0 4
exec-timeout 0 0
privilege level 15
password 7 07003B56470C4854
login
transport input telnet ssh
line vty 5 181
exec-timeout 0 0
privilege level 15
password 7 07003B56470C4854
login
transport input telnet ssh
!
!
end
r2620_01#sh run | begin ssh
transport input telnet ssh
line vty 5 181
exec-timeout 0 0
privilege level 15
password 7 07003B56470C4854
login
transport input telnet ssh
!
!
end
you get the idea...
routing quick q and a...
r1 and r2 are using a dynamic routing protocol, and as the soldiers would say, "to get from the left to the right"
host01 wants to communicate with host02
what is the source ip address? (think interfaces, not numbers)
what is the destination ip address?
what is the default gateway for sw1 and sw2 respectively?
what is the source hardware address (from the perspective of host01)?
once the packet traverses the network, what source hardware address will host02 see?
what movie is the quote from?
comment for answers, or figure it out yourself...
Monday, November 21, 2011
rack mounted...
it ain't uber-geek but it's mine... voice coming later this week...
i have rack wood...
Friday, November 18, 2011
Wednesday, November 16, 2011
eigorp...
EIGRP
live it, love it...
eigrp is a cisco proprietary hybrid routing protocol. it uses an autonomous sytem to
describe the set of contiguous routers that use the same protocol and routing information.
it includes the subnet mask in its updates (vlsm capable)
eigrp has both distance vector and link state qualities. it sends distance vector network
information and the costs associated with reaching those networks from the vantage point of the
advertising router.
its link state characteristics include sync'ing routing tables between neighbors at startup and
sending updates when the topology changes
eigrp uses rtp (reliable transport protocol)
has efficient neighbor discovery
uses dual (diffusing update algorithm) for best path selection
supports vlsm
it also uses protocol dependant modules which is a way of saying it can support multiple
protocols such as appletalk and ipx, much like is-is can support ip and clns... but who in their
right mind uses appletalk and ipx anymore...
grrrrrrrrrrrrp...
live it, love it...
eigrp is a cisco proprietary hybrid routing protocol. it uses an autonomous sytem to
describe the set of contiguous routers that use the same protocol and routing information.
it includes the subnet mask in its updates (vlsm capable)
eigrp has both distance vector and link state qualities. it sends distance vector network
information and the costs associated with reaching those networks from the vantage point of the
advertising router.
its link state characteristics include sync'ing routing tables between neighbors at startup and
sending updates when the topology changes
eigrp uses rtp (reliable transport protocol)
has efficient neighbor discovery
uses dual (diffusing update algorithm) for best path selection
supports vlsm
it also uses protocol dependant modules which is a way of saying it can support multiple
protocols such as appletalk and ipx, much like is-is can support ip and clns... but who in their
right mind uses appletalk and ipx anymore...
grrrrrrrrrrrrp...
Monday, November 14, 2011
certification regurgitation...
a router routes... how many times have you heard that bullshit... here's another:
a router routes routed protocols using routing protocols...
in an effort to keep this mysterious business simpler, the instructors and writers make it more esoteric, confounding the whole thing...
a router is a packet's facilitator along the path of least resistance towards its destination...
quick quiz:
1 question, get it right or fail the test...
what does the ctrl+n key sequence perform...
ask a ccie this ridiculous question and i bet he/she won't be able to answer...
the biggest problem with ccna certification is that as you progress, get better and stronger, you still have to remember that kind of garbage...
a router routes routed protocols using routing protocols...
in an effort to keep this mysterious business simpler, the instructors and writers make it more esoteric, confounding the whole thing...
a router is a packet's facilitator along the path of least resistance towards its destination...
quick quiz:
1 question, get it right or fail the test...
what does the ctrl+n key sequence perform...
ask a ccie this ridiculous question and i bet he/she won't be able to answer...
the biggest problem with ccna certification is that as you progress, get better and stronger, you still have to remember that kind of garbage...
Sunday, November 13, 2011
ppp'ing...
globally set the username as the hostname of the other router, password the same on each router, and encap ppp on each interface and you're ppp'ing...
to wit:
r2620_01#sh int s0/0
Serial0/0 is up, line protocol is up
Hardware is PowerQUICC Serial
Internet address is 30.0.0.1/24
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: IPCP, CDPCP, loopback not set
Keepalive set (10 sec)
r2620_01#sh int s0/1
Serial0/1 is up, line protocol is up
Hardware is PowerQUICC Serial
Internet address is 20.0.0.1/24
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: IPCP, CDPCP, loopback not set
Keepalive set (10 sec)
and:
r2620_03#ping 2.2.2.2
(ping from router 3 to router 2 via router 1)
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 60/67/80 ms
r2620_03#
finally,
sh ip int will not show you the new encapsulation, sh int does...
to wit:
r2620_01#sh int s0/0
Serial0/0 is up, line protocol is up
Hardware is PowerQUICC Serial
Internet address is 30.0.0.1/24
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: IPCP, CDPCP, loopback not set
Keepalive set (10 sec)
r2620_01#sh int s0/1
Serial0/1 is up, line protocol is up
Hardware is PowerQUICC Serial
Internet address is 20.0.0.1/24
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation PPP, LCP Open
Open: IPCP, CDPCP, loopback not set
Keepalive set (10 sec)
and:
r2620_03#ping 2.2.2.2
(ping from router 3 to router 2 via router 1)
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 60/67/80 ms
r2620_03#
finally,
sh ip int will not show you the new encapsulation, sh int does...
Saturday, November 12, 2011
sh ip protozoan...
note: the process id for router 1 is 1
the router id is the lo0 1.1.1.1
the networks are the directly connected networks, 1 loopback, 10 and 11 are serials and 192 is fa0/0 to the 3550
and the gateways are all 4 loopbacks
the administrative distance is 110...
that's why i had to whack eigrp
r2620_01#sh ip proto
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 1.1.1.1
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
1.1.1.0 0.0.0.255 area 0
10.0.0.0 0.0.0.255 area 0
11.0.0.0 0.0.0.255 area 0
192.168.1.0 0.0.0.255 area 0
Reference bandwidth unit is 100 mbps
Routing Information Sources:
Gateway Distance Last Update
3.3.3.3 110 00:53:34
2.2.2.2 110 00:53:34
1.1.1.1 110 00:58:40
100.0.0.1 110 00:50:08
Distance: (default is 110)
r2620_01#
the router id is the lo0 1.1.1.1
the networks are the directly connected networks, 1 loopback, 10 and 11 are serials and 192 is fa0/0 to the 3550
and the gateways are all 4 loopbacks
the administrative distance is 110...
that's why i had to whack eigrp
r2620_01#sh ip proto
Routing Protocol is "ospf 1"
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Router ID 1.1.1.1
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Maximum path: 4
Routing for Networks:
1.1.1.0 0.0.0.255 area 0
10.0.0.0 0.0.0.255 area 0
11.0.0.0 0.0.0.255 area 0
192.168.1.0 0.0.0.255 area 0
Reference bandwidth unit is 100 mbps
Routing Information Sources:
Gateway Distance Last Update
3.3.3.3 110 00:53:34
2.2.2.2 110 00:53:34
1.1.1.1 110 00:58:40
100.0.0.1 110 00:50:08
Distance: (default is 110)
r2620_01#
say hello ospf
don't forget to issue un all first, then:
r2620_01#debug ip ospf hello
OSPF hello events debugging is on
r2620_01#
1d08h: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial0/0 11.0.0.3
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 2.2.2.2 area 0 from Serial0/1 10.0.0.2
1d08h: OSPF: End of hello processing
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.50
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/0 from 11.0.0.1
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/1 from 10.0.0.1
1d08h: OSPF: Rcv hello from 100.0.0.1 area 0 from FastEthernet0/0 192.168.1.100
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial0/0 11.0.0.3
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 2.2.2.2 area 0 from Serial0/1 10.0.0.2
1d08h: OSPF: End of hello processing
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.50
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/0 from 11.0.0.1
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/1 from 10.0.0.1
1d08h: OSPF: Rcv hello from 100.0.0.1 area 0 from FastEthernet0/0 192.168.1.100
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial0/0 11.0.0.3
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 2.2.2.2 area 0 from Serial0/1 10.0.0.2
1d08h: OSPF: End of hello processing
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.50
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/0 from 11.0.0.1
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/1 from 10.0.0.1
1d08h: OSPF: Rcv hello from 100.0.0.1 area 0 from FastEthernet0/0 192.168.1.100
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial0/0 11.0.0.3
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 2.2.2.2 area 0 from Serial0/1 10.0.0.2
1d08h: OSPF: End of hello processing
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.50
all possible debugging has been turned off
r2620_01#
it's a whole new world out there...
r2620_01#debug ip ospf hello
OSPF hello events debugging is on
r2620_01#
1d08h: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial0/0 11.0.0.3
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 2.2.2.2 area 0 from Serial0/1 10.0.0.2
1d08h: OSPF: End of hello processing
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.50
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/0 from 11.0.0.1
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/1 from 10.0.0.1
1d08h: OSPF: Rcv hello from 100.0.0.1 area 0 from FastEthernet0/0 192.168.1.100
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial0/0 11.0.0.3
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 2.2.2.2 area 0 from Serial0/1 10.0.0.2
1d08h: OSPF: End of hello processing
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.50
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/0 from 11.0.0.1
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/1 from 10.0.0.1
1d08h: OSPF: Rcv hello from 100.0.0.1 area 0 from FastEthernet0/0 192.168.1.100
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial0/0 11.0.0.3
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 2.2.2.2 area 0 from Serial0/1 10.0.0.2
1d08h: OSPF: End of hello processing
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.50
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/0 from 11.0.0.1
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on Serial0/1 from 10.0.0.1
1d08h: OSPF: Rcv hello from 100.0.0.1 area 0 from FastEthernet0/0 192.168.1.100
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 3.3.3.3 area 0 from Serial0/0 11.0.0.3
1d08h: OSPF: End of hello processing
1d08h: OSPF: Rcv hello from 2.2.2.2 area 0 from Serial0/1 10.0.0.2
1d08h: OSPF: End of hello processing
1d08h: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 192.168.1.50
all possible debugging has been turned off
r2620_01#
it's a whole new world out there...
ospf is all up in here...
r2620_01#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/65] via 10.0.0.2, 00:05:52, Serial0/1
100.0.0.0/32 is subnetted, 1 subnets
O 100.0.0.1 [110/2] via 192.168.1.100, 00:02:26, FastEthernet0/0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/65] via 11.0.0.3, 00:05:52, Serial0/0
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Serial0/1
11.0.0.0/24 is subnetted, 1 subnets
C 11.0.0.0 is directly connected, Serial0/0
C 192.168.1.0/24 is directly connected, FastEthernet0/0
r2620_01#
my soho is now an ospf network...
how?
went to router 3 and added ospf (router ospf 3, the 2 networks)
same to router 2 and added the 2 directly connected networks,
then router 1 and it's 4 directly connected networks,
then went back and whacked eigrp on each router,
hopped over to the 3550, added ospf and it's directly conected networks, whacked eigrp, and
now everybody is pinging everybody...
took about 5 minutes...
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
2.0.0.0/32 is subnetted, 1 subnets
O 2.2.2.2 [110/65] via 10.0.0.2, 00:05:52, Serial0/1
100.0.0.0/32 is subnetted, 1 subnets
O 100.0.0.1 [110/2] via 192.168.1.100, 00:02:26, FastEthernet0/0
3.0.0.0/32 is subnetted, 1 subnets
O 3.3.3.3 [110/65] via 11.0.0.3, 00:05:52, Serial0/0
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Serial0/1
11.0.0.0/24 is subnetted, 1 subnets
C 11.0.0.0 is directly connected, Serial0/0
C 192.168.1.0/24 is directly connected, FastEthernet0/0
r2620_01#
my soho is now an ospf network...
how?
went to router 3 and added ospf (router ospf 3, the 2 networks)
same to router 2 and added the 2 directly connected networks,
then router 1 and it's 4 directly connected networks,
then went back and whacked eigrp on each router,
hopped over to the 3550, added ospf and it's directly conected networks, whacked eigrp, and
now everybody is pinging everybody...
took about 5 minutes...
xmodem...
i was getting tired by the last router upgrade from smi to emi...
but first a moment from our sponsor, the 3550 switch...
the default baud rate out of the box is 9600 for a console connection, however, did you know that this cannot be changed using the configuration register... 3560's either... so i have what appears to be a baud rate incompatibility with my console connection because after setting the term to 9600, 8, none. 1, i get weird ascii creatures... that's a pain in the ass... hope i don't end up in rommon mode after next reload...
back to the ios upgrade... i delete the current ios in flash, copy run start, and reload the router...
shit...
after it came back it couldn't find an ios... flash was empty... i should have gone to bed... like i said, i was tired... it's been years since i've done an xmodem ios transfer... i set the baud rate on the router to 115200 and xmodemed away... 2 hours later i finally had an ios in flash again... duh...
here's the key... don't be a hero and delete flash from the cli by hand... let copy tftp flash do it for you... it will prompt you to erase before loading the new ios, and you won't be sitting there all night watching exclamation points go across your damn screen because you bounced the router before you loaded the ios...
i am a dumbass...
but first a moment from our sponsor, the 3550 switch...
the default baud rate out of the box is 9600 for a console connection, however, did you know that this cannot be changed using the configuration register... 3560's either... so i have what appears to be a baud rate incompatibility with my console connection because after setting the term to 9600, 8, none. 1, i get weird ascii creatures... that's a pain in the ass... hope i don't end up in rommon mode after next reload...
back to the ios upgrade... i delete the current ios in flash, copy run start, and reload the router...
shit...
after it came back it couldn't find an ios... flash was empty... i should have gone to bed... like i said, i was tired... it's been years since i've done an xmodem ios transfer... i set the baud rate on the router to 115200 and xmodemed away... 2 hours later i finally had an ios in flash again... duh...
here's the key... don't be a hero and delete flash from the cli by hand... let copy tftp flash do it for you... it will prompt you to erase before loading the new ios, and you won't be sitting there all night watching exclamation points go across your damn screen because you bounced the router before you loaded the ios...
i am a dumbass...
spanning-treed...
i asked michael the network cat exactly what it is that spanning-tree does...
he replied, it prevents switching loops...
precisely...
so in case you don't have a meshed network, what then michael?
it causes a lot of traffic, slows down your ports, doesn't block any ports because there are no redundant links, but gives you nice output and bridge and port status information, lots of debugging stuff if you want to see it, and many other features that will be tested by cisco...
ok then... the right answer is the cisco answer...
he replied, it prevents switching loops...
precisely...
so in case you don't have a meshed network, what then michael?
it causes a lot of traffic, slows down your ports, doesn't block any ports because there are no redundant links, but gives you nice output and bridge and port status information, lots of debugging stuff if you want to see it, and many other features that will be tested by cisco...
ok then... the right answer is the cisco answer...
Thursday, November 10, 2011
Monday, November 7, 2011
saran wrap...
when you receive a cisco switch it is by default set to server mode out of the box... be sure to set it to transparent mode before deployment...
Server
can create, add, delete and/or change vlan information. these changes are added throughout the VTP domain
Client
listen for advertisements and modify their own configurations as a result. a server is required by the client for vlan changes. a client cannot create, add or delete vlans
Transparent
can forward or receive vlan advertisements but otherwise do not participate in the domain...
you can see right through them... so there...
Server
can create, add, delete and/or change vlan information. these changes are added throughout the VTP domain
Client
listen for advertisements and modify their own configurations as a result. a server is required by the client for vlan changes. a client cannot create, add or delete vlans
Transparent
can forward or receive vlan advertisements but otherwise do not participate in the domain...
you can see right through them... so there...
Sunday, November 6, 2011
rip and eigrp together...
follow the bouncing prompts...
r2620_01#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
R 2.0.0.0/8 [120/1] via 10.0.0.2, 00:00:10, Serial0/1
R 100.0.0.0/8 [120/1] via 192.168.1.100, 00:00:20, FastEthernet0/0
R 3.0.0.0/8 [120/1] via 11.0.0.3, 00:00:12, Serial0/0
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Serial0/1
11.0.0.0/24 is subnetted, 1 subnets
C 11.0.0.0 is directly connected, Serial0/0
C 192.168.1.0/24 is directly connected, FastEthernet0/0
r2620_01#
sw3550#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
R 1.0.0.0/8 [120/1] via 192.168.1.50, 00:00:13, Vlan1
R 2.0.0.0/8 [120/2] via 192.168.1.50, 00:00:13, Vlan1
100.0.0.0/24 is subnetted, 1 subnets
C 100.0.0.0 is directly connected, Loopback0
R 3.0.0.0/8 [120/2] via 192.168.1.50, 00:00:13, Vlan1
R 10.0.0.0/8 [120/1] via 192.168.1.50, 00:00:13, Vlan1
R 11.0.0.0/8 [120/1] via 192.168.1.50, 00:00:13, Vlan1
C 192.168.1.0/24 is directly connected, Vlan1
sw3550#
then eigrp comes into the mix...
r2620_01#config t
Enter configuration commands, one per line. End with CNTL/Z.
r2620_01(config)#router eigrp 1
r2620_01(config-router)#network 1.0.0.0
r2620_01(config-router)# network 10.0.0.0
r2620_01(config-router)# network 11.0.0.0
r2620_01(config-router)# network 192.168.1.0
r2620_01(config-router)#no auto-summ
r2620_01(config-router)#end
r2620_01#
after the other 2 routers have been updated with eigrp here is the new routing table...
r2620_01#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
2.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
R 2.0.0.0/8 [120/1] via 10.0.0.2, 00:00:19, Serial0/1
D 2.2.2.0/24 [90/2297856] via 10.0.0.2, 00:05:26, Serial0/1
R 100.0.0.0/8 [120/1] via 192.168.1.100, 00:00:21, FastEthernet0/0
3.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
R 3.0.0.0/8 [120/1] via 11.0.0.3, 00:00:05, Serial0/0
D 3.3.3.0/24 [90/2297856] via 11.0.0.3, 00:01:20, Serial0/0
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Serial0/1
11.0.0.0/24 is subnetted, 1 subnets
C 11.0.0.0 is directly connected, Serial0/0
C 192.168.1.0/24 is directly connected, FastEthernet0/0
r2620_01#
r2620_02#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 1.1.1.0/24 [90/2297856] via 10.0.0.1, 00:24:20, Serial0/0
R 1.0.0.0/8 [120/1] via 10.0.0.1, 00:00:00, Serial0/0
2.0.0.0/24 is subnetted, 1 subnets
C 2.2.2.0 is directly connected, Loopback0
R 100.0.0.0/8 [120/2] via 10.0.0.1, 00:00:00, Serial0/0
3.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 3.3.3.0/24 [90/2809856] via 10.0.0.1, 00:20:14, Serial0/0
R 3.0.0.0/8 [120/2] via 10.0.0.1, 00:00:00, Serial0/0
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Serial0/0
11.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 11.0.0.0/24 [90/2681856] via 10.0.0.1, 00:24:20, Serial0/0
R 11.0.0.0/8 [120/1] via 10.0.0.1, 00:00:04, Serial0/0
D 192.168.1.0/24 [90/2172416] via 10.0.0.1, 00:24:24, Serial0/0
r2620_02#
r2620_02#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
1.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 1.1.1.0/24 [90/2297856] via 10.0.0.1, 00:24:20, Serial0/0
R 1.0.0.0/8 [120/1] via 10.0.0.1, 00:00:00, Serial0/0
2.0.0.0/24 is subnetted, 1 subnets
C 2.2.2.0 is directly connected, Loopback0
R 100.0.0.0/8 [120/2] via 10.0.0.1, 00:00:00, Serial0/0
3.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 3.3.3.0/24 [90/2809856] via 10.0.0.1, 00:20:14, Serial0/0
R 3.0.0.0/8 [120/2] via 10.0.0.1, 00:00:00, Serial0/0
10.0.0.0/30 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Serial0/0
11.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 11.0.0.0/24 [90/2681856] via 10.0.0.1, 00:24:20, Serial0/0
R 11.0.0.0/8 [120/1] via 10.0.0.1, 00:00:04, Serial0/0
D 192.168.1.0/24 [90/2172416] via 10.0.0.1, 00:24:24, Serial0/0
r2620_02#
look at those friggin d's up in there...
and the 3550 wants in too...
only the 3550 is still stuck with rip version 2...
sw3550#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
R 1.0.0.0/8 [120/1] via 192.168.1.50, 00:00:25, Vlan1
R 2.0.0.0/8 [120/2] via 192.168.1.50, 00:00:25, Vlan1
100.0.0.0/24 is subnetted, 1 subnets
C 100.0.0.0 is directly connected, Loopback0
R 3.0.0.0/8 [120/2] via 192.168.1.50, 00:00:25, Vlan1
R 10.0.0.0/8 [120/1] via 192.168.1.50, 00:00:25, Vlan1
R 11.0.0.0/8 [120/1] via 192.168.1.50, 00:00:25, Vlan1
C 192.168.1.0/24 is directly connected, Vlan1
sw3550#
and the 2950's have a say in the matter as well on the other side of the 3550...
sw2950_02#ping 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 32/34/44 ms
sw2950_02#
rip still hangs in the background but rips' administrative distance just got hammered by eigrp...
(output from r2601_01's sh run)
router eigrp 1
network 1.0.0.0
network 10.0.0.0
network 11.0.0.0
network 192.168.1.0
no auto-summary
!
router rip
version 2
network 1.0.0.0
network 10.0.0.0
network 11.0.0.0
network 192.168.1.0
eigrp and rip; like peas and carrots...
include...
pipe running-config through include with the regular expression you want to pick out, ie:
sw3550#sh run | include service
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
sw3550#
sw3550#sh run | inc network
network 100.0.0.0
network 192.168.1.0
sw3550#
r2620_01#sh run | include interface
interface Loopback0
interface FastEthernet0/0
interface Serial0/0
interface Serial0/1
r2620_01#
r2620_01#sh run | inc buttcheese
r2620_01#
that one didn't work...
sw3550#sh run | include service
no service pad
service timestamps debug uptime
service timestamps log uptime
service password-encryption
sw3550#
sw3550#sh run | inc network
network 100.0.0.0
network 192.168.1.0
sw3550#
r2620_01#sh run | include interface
interface Loopback0
interface FastEthernet0/0
interface Serial0/0
interface Serial0/1
r2620_01#
r2620_01#sh run | inc buttcheese
r2620_01#
that one didn't work...
junk in the trunk...
sw2950_02(config)#int fa0/2
sw2950_02(config-if)#switchport nonegotiate
first, DTP (dynamic trunking protocol) is cisco proprietary and will not work with gray market switches... use nonegotiate in a mixed environment... this disables DTP, will only become a trunk with ON or NONEGOTIATE ports, and port ranges are not allowed with this command
sw2950_02(config)#int fa0/2
sw2950_02(config-if)#sw mode trunk
trunking is on... DTP signals are sent to the other connected port to initiate trunking if it is ON, AUTO, or DESIRABLE
if:
sw2950_02(config-if)#sw mode dynamic desirable
the port will become a trunk after detecting DTP signals of ON, AUTO or DESIRABLE from the connected port
if:
sw2950_02(config-if)#sw mod dyn auto
the port will become a trunk if the other port is ON or DESIRABLE
if:
sw2950_02(config-if)#no sw mod trunk
trunking and DTP are disabled and this is the desired state for access ports; no dynamic establishments can occur
today's post was brought to you by Michael the network cat...
Guster the love muffin...
and Craze, the queen of the domain...
sw2950_02(config-if)#switchport nonegotiate
first, DTP (dynamic trunking protocol) is cisco proprietary and will not work with gray market switches... use nonegotiate in a mixed environment... this disables DTP, will only become a trunk with ON or NONEGOTIATE ports, and port ranges are not allowed with this command
sw2950_02(config)#int fa0/2
sw2950_02(config-if)#sw mode trunk
trunking is on... DTP signals are sent to the other connected port to initiate trunking if it is ON, AUTO, or DESIRABLE
if:
sw2950_02(config-if)#sw mode dynamic desirable
the port will become a trunk after detecting DTP signals of ON, AUTO or DESIRABLE from the connected port
if:
sw2950_02(config-if)#sw mod dyn auto
the port will become a trunk if the other port is ON or DESIRABLE
if:
sw2950_02(config-if)#no sw mod trunk
trunking and DTP are disabled and this is the desired state for access ports; no dynamic establishments can occur
today's post was brought to you by Michael the network cat...
and Craze, the queen of the domain...
Saturday, November 5, 2011
auto-summarization...
from the horse's mouth,
http://www.cisco.com/en/US/docs/ios/12_2/iproute/command/reference/1rfeigrp.html#wp1017389
Route summarization reduces the amount of routing information in the routing tables.
By default, Border Gateway Protocol (BGP) does not accept subnets redistributed from an Interior Gateway Protocol (IGP). To advertise and carry subnet routes in BGP, use an explicit network command or the no auto-summary command. If you disable automatic summarization and have not entered a network command, you will not advertise network routes for networks with subnet routes unless they contain a summary route.
Enhanced Interior Gateway Routing Protocol (EIGRP) summary routes are given an administrative distance value of 5. You cannot configure this value.
Routing Information Protocol (RIP) Version 1 always uses automatic summarization. If you are using RIP Version 2, you can turn off automatic summarization by specifying the no auto-summary command. Disable automatic summarization if you must perform routing between disconnected (discontiguous) subnets. When automatic summarization is off, subnets are advertised.
Examples
The following example disables automatic summarization for EIGRP process 1:
router eigrp 1
no auto-summary
I've seen test questions that give a range of 4 IP addresses with slash notation, and ask that you choose the best summary route or rather the route that the protocol will select...
ok 4 addresses in the RANGE, say class B
rfc1918 states the default slash notation for class B is /16
what power of 2 = our RANGE? (2^2 = 4) the answer is 2
now, nice and easy, we have 4 addresses in the question's RANGE, there are 16 subnet bits in Class B,
subtract 2 from the default class (16 - 2 = 14) so apply this mask /14 to the first IP address in the question's range and you've solved the problem...
if we had 16 IP addresses in the question, again Class B, what would our power of 2 be?
4 (2^4 = 16)
what is 16 - 4?
apply /12 to the first address in the range...
breathe in...
http://www.cisco.com/en/US/docs/ios/12_2/iproute/command/reference/1rfeigrp.html#wp1017389
Route summarization reduces the amount of routing information in the routing tables.
By default, Border Gateway Protocol (BGP) does not accept subnets redistributed from an Interior Gateway Protocol (IGP). To advertise and carry subnet routes in BGP, use an explicit network command or the no auto-summary command. If you disable automatic summarization and have not entered a network command, you will not advertise network routes for networks with subnet routes unless they contain a summary route.
Enhanced Interior Gateway Routing Protocol (EIGRP) summary routes are given an administrative distance value of 5. You cannot configure this value.
Routing Information Protocol (RIP) Version 1 always uses automatic summarization. If you are using RIP Version 2, you can turn off automatic summarization by specifying the no auto-summary command. Disable automatic summarization if you must perform routing between disconnected (discontiguous) subnets. When automatic summarization is off, subnets are advertised.
Examples
The following example disables automatic summarization for EIGRP process 1:
router eigrp 1
no auto-summary
I've seen test questions that give a range of 4 IP addresses with slash notation, and ask that you choose the best summary route or rather the route that the protocol will select...
ok 4 addresses in the RANGE, say class B
rfc1918 states the default slash notation for class B is /16
what power of 2 = our RANGE? (2^2 = 4) the answer is 2
now, nice and easy, we have 4 addresses in the question's RANGE, there are 16 subnet bits in Class B,
subtract 2 from the default class (16 - 2 = 14) so apply this mask /14 to the first IP address in the question's range and you've solved the problem...
if we had 16 IP addresses in the question, again Class B, what would our power of 2 be?
4 (2^4 = 16)
what is 16 - 4?
apply /12 to the first address in the range...
breathe in...
rip ver 2...
just replaced rip with version 2...
and the networks populate themselves... hence
w3550(config)#router rip
sw3550(config-router)#ver 2
sw3550(config-router)#end
sw3550#sh ip protocols
Routing Protocol is "rip"
Sending updates every 30 seconds, next due in 2 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: rip
Default version control: send version 2, receive version 2
Interface Send Recv Triggered RIP Key-chain
Vlan1 2 2
Loopback0 2 2
Automatic network summarization is in effect
Maximum path: 4
Routing for Networks:
100.0.0.0
172.16.0.0
192.168.1.0
Routing Information Sources:
Gateway Distance Last Update
10.0.0.2 120 18:09:26
192.168.1.100 120 17:03:28
192.168.1.50 120 00:00:19
192.168.1.20 120 1d05h
172.16.0.2 120 17:46:21
Distance: (default is 120)
beautiful...
and the networks populate themselves... hence
w3550(config)#router rip
sw3550(config-router)#ver 2
sw3550(config-router)#end
sw3550#sh ip protocols
Routing Protocol is "rip"
Sending updates every 30 seconds, next due in 2 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: rip
Default version control: send version 2, receive version 2
Interface Send Recv Triggered RIP Key-chain
Vlan1 2 2
Loopback0 2 2
Automatic network summarization is in effect
Maximum path: 4
Routing for Networks:
100.0.0.0
172.16.0.0
192.168.1.0
Routing Information Sources:
Gateway Distance Last Update
10.0.0.2 120 18:09:26
192.168.1.100 120 17:03:28
192.168.1.50 120 00:00:19
192.168.1.20 120 1d05h
172.16.0.2 120 17:46:21
Distance: (default is 120)
beautiful...
bootcamp...
i was in a real boot camp in '87, Marine style, parris island, hardcore... 11 weeks of agony... then i went to electronics school for a year at 29 palms, california, one of the meaner places on earth... but back to bootcamp... i have never experienced the phenomenon...
my thought is study, study odom, lammle, there's tons of instructional stuff on youtube, get your hands on gns3, buy a layer 3 switch and a layer 2 switch, ebay is often giving this away, check out blindhog, forums, get a cco account at cisco's learning center (don't waste your money on sims, and stay far away from braindumps) then after you've done all that...
then maybe bootcamp prior to testing...
i'd really like to hear about anyone with experience in one of these bootcamps... please comment or email me, b.osgood2011@gmail.com... with permission, i'd be glad to post anything you might have about training, what worked, what didn't, study material, recommendations, tips, tricks, you name it... i'll put you up in lights right next to michael the network cat...
i mean it...
my thought is study, study odom, lammle, there's tons of instructional stuff on youtube, get your hands on gns3, buy a layer 3 switch and a layer 2 switch, ebay is often giving this away, check out blindhog, forums, get a cco account at cisco's learning center (don't waste your money on sims, and stay far away from braindumps) then after you've done all that...
then maybe bootcamp prior to testing...
i'd really like to hear about anyone with experience in one of these bootcamps... please comment or email me, b.osgood2011@gmail.com... with permission, i'd be glad to post anything you might have about training, what worked, what didn't, study material, recommendations, tips, tricks, you name it... i'll put you up in lights right next to michael the network cat...
i mean it...
OZLAN...
the last day and a half has been enlightening... i used to support a large cisco network for many years, and the needs of that community... those needs were not my needs but i still had some great experiences... having my own equipment and doing with it exactly as i want allows unlimited freedom... there is only so much experimentation one can do under production circumstances...
i have my 2950's and 2620's currently running rip and communicating with each other and the internet... i'll soon move on to ripv2, eigrp, ospf, etc... i have vlans for hosts and printers, trunks are up and running, serial connections are singing, and i couldn't be happier... also, if you have a chance to get your hands on a 3550 or 3560, beg borrow or steal...
this is a new phase for me, and as i move to different protocols with OZLAN and make new configurations, i'll erase start on all the devices, and rebuild them as if it was all new again... and you will all feel the pain with me...
i have my 2950's and 2620's currently running rip and communicating with each other and the internet... i'll soon move on to ripv2, eigrp, ospf, etc... i have vlans for hosts and printers, trunks are up and running, serial connections are singing, and i couldn't be happier... also, if you have a chance to get your hands on a 3550 or 3560, beg borrow or steal...
this is a new phase for me, and as i move to different protocols with OZLAN and make new configurations, i'll erase start on all the devices, and rebuild them as if it was all new again... and you will all feel the pain with me...
Friday, November 4, 2011
some network output...
i'm starting out with rip, then eigrp and ospf... you can see below how it's shaping up... still have many things to do, vlan and interface descriptions, ios upgrades, serial connections, trunking, stp, vtp, etc... i'd like to say i'm having fun, but it's gone from a treat to an obsession... vpn, firewall, sdm, frame... damn...
sw3550#sh cdp neigh
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone
Device ID Local Intrfce Holdtme Capability Platform Port ID
r2620_03 Fas 0/18 148 R 2620XM Fas 0/0
r2620_02 Fas 0/8 123 R S I Cisco 2620Fas 0/0
r2620_01 Fas 0/1 176 R 2620XM Fas 0/0
sw3550#
sw3550#sh ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is not set
R 1.0.0.0/8 [120/1] via 192.168.1.100, 00:00:07, Vlan1
R 2.0.0.0/8 [120/1] via 10.0.0.2, 00:00:21, Vlan2
C 100.0.0.0/8 is directly connected, Loopback0
R 3.0.0.0/8 [120/1] via 172.16.0.2, 00:00:14, Vlan3
C 172.16.0.0/16 is directly connected, Vlan3
10.0.0.0/24 is subnetted, 1 subnets
C 10.0.0.0 is directly connected, Vlan2
C 192.168.1.0/24 is directly connected, Vlan1
sw3550#
as an old college friend of mine used to say:
may the bulls run wild...
Thursday, November 3, 2011
a snap of CMS...
the 3550 i got yesterday on CMS... more later... it's simply embarrassing in light of uber-geek...
why? how? wtf...
why hasn't cisco fabricated rj-45 to usb console cables?
so you can go out and spend 40 bucks to buy a 3rd party adapter...
when a root bridge is established, why is its priority 32769?
because of sys-id-ext 1
how often does spanning-tree send hellos?
every 2 seconds
if you debug spanning-tree you can expect a lot of output at the console, so how do you preempt this?
by issuing the command un all before issuing the command debug spanning-tree... why?
so you can stop the madness by pressing up arrow and enter, to turn it off...
from a telnet session you issue debug spanning-tree... why isn't there any output to the screen?
you haven't issued terminal monitor from privileged-exec mode, that's why...
to accomplish convergence, what states must the ports be in?
blocking and forwarding
and how long does convergence take?
50 seconds
how do you turn off stp to get rid of this 50 second shit on a port?
in interface configuration mode use spanning-tree portfast and the the interface will move to forwarding on linkup
so you can go out and spend 40 bucks to buy a 3rd party adapter...
when a root bridge is established, why is its priority 32769?
because of sys-id-ext 1
how often does spanning-tree send hellos?
every 2 seconds
if you debug spanning-tree you can expect a lot of output at the console, so how do you preempt this?
by issuing the command un all before issuing the command debug spanning-tree... why?
so you can stop the madness by pressing up arrow and enter, to turn it off...
from a telnet session you issue debug spanning-tree... why isn't there any output to the screen?
you haven't issued terminal monitor from privileged-exec mode, that's why...
to accomplish convergence, what states must the ports be in?
blocking and forwarding
and how long does convergence take?
50 seconds
how do you turn off stp to get rid of this 50 second shit on a port?
in interface configuration mode use spanning-tree portfast and the the interface will move to forwarding on linkup
Wednesday, November 2, 2011
a new beginning...
my first shipment arrived today, the 3550, i expect the rest of the gear tomorrow... it's kind of weird having the shit in my apartment... it'll be a constant reminder; configure me, connect me, make me go to porn sites... i'll do pictures tomorrow once i have them racked...
so i take the switch out of the box, set it on a stand for now, grab the console cable and i'm ready to connect it to my laptop... no serial port... not a problem... i break out the old desktop, monitor, etc, power it up and i'm all set... no serial port on that either and that's got to be five years old by now... damn... off to office max, nice that it's just up the road, and i look around a bit... over ten bucks for a power cable, nearly thirty for a long rj-45... i turn a corner and there is the section i'm looking for... 37 dollars for a serial to usb adapter... i have these visions that i'm about to nickel and dime myself into the poor house with this project... all right, buy it, return it before 14 days are up, and get a cheaper one on line... not a chance, 30 bucks on line not including shipping... good God...
had to install software for it also... connect it up, run putty, select serial, com1, defaults to 8, none, and 1
and i get errors; serial port not found... go to control-panel, system, hardware, (xp machine) and there it is... on com3...
works great... connected it up through the wireless router to the cable modem and i'm pinging the time warner gateway within moments... routers and more switches tomorrow...
so i take the switch out of the box, set it on a stand for now, grab the console cable and i'm ready to connect it to my laptop... no serial port... not a problem... i break out the old desktop, monitor, etc, power it up and i'm all set... no serial port on that either and that's got to be five years old by now... damn... off to office max, nice that it's just up the road, and i look around a bit... over ten bucks for a power cable, nearly thirty for a long rj-45... i turn a corner and there is the section i'm looking for... 37 dollars for a serial to usb adapter... i have these visions that i'm about to nickel and dime myself into the poor house with this project... all right, buy it, return it before 14 days are up, and get a cheaper one on line... not a chance, 30 bucks on line not including shipping... good God...
had to install software for it also... connect it up, run putty, select serial, com1, defaults to 8, none, and 1
and i get errors; serial port not found... go to control-panel, system, hardware, (xp machine) and there it is... on com3...
works great... connected it up through the wireless router to the cable modem and i'm pinging the time warner gateway within moments... routers and more switches tomorrow...
is this heaven or hell...
more from this guys basement here... http://smorris.uber-geek.net/lab.htm
i want to party with this guy...
quiz...
1) what is the root bridge default priority?
2) what is the DOD equivalent of the OSI transport layer?
3) what is 90.37.200.31 in binary?
4) /17. how many subnets and hosts?
5) what is the hop count for OSPF?
6) what kind of traffic does IGMP service?
7) IP is connection oriented? true or false
8) what is 2 to the 15th?
9) what does CHAP stand for?
10) how do you turn off CDP on an interface?
bonus: what is the theme of this quiz?
answers after the trip
2) what is the DOD equivalent of the OSI transport layer?
3) what is 90.37.200.31 in binary?
4) /17. how many subnets and hosts?
5) what is the hop count for OSPF?
6) what kind of traffic does IGMP service?
7) IP is connection oriented? true or false
8) what is 2 to the 15th?
9) what does CHAP stand for?
10) how do you turn off CDP on an interface?
bonus: what is the theme of this quiz?
answers after the trip
contivity takes a bow...
the nortel contivity firewall was reaching end of life, at least my life, so i seized the opportunity to introduce another cisco system to the community; the ASA-5520...
the 5520 naturally had its roots in pix technology, so i ordered it and also ordered a book... the book that was available was geared towards the 5520 but it was mostly pix with a few hints about the new (for us) firewall...
i was a little sad to see contivity go... she had been a good box and over the years i had become accustomed to it, pretty good at its filtering features actually, but she had had her day and i always wanted more cisco wherever i could get it...remember, i was always fighting the nortel monster...
the 5520 took about a half a day to implement but she came around... the front end was a lot like what SDM is now... not awfully friendly but serviceable... the feature set was extensive and whereas the VPN of the contivity was pretty straight forward, 5520 was a little more complicated... my long term cisco hopes were slowly, very slowly, coming to fruition...
the 5520 naturally had its roots in pix technology, so i ordered it and also ordered a book... the book that was available was geared towards the 5520 but it was mostly pix with a few hints about the new (for us) firewall...
i was a little sad to see contivity go... she had been a good box and over the years i had become accustomed to it, pretty good at its filtering features actually, but she had had her day and i always wanted more cisco wherever i could get it...remember, i was always fighting the nortel monster...
the 5520 took about a half a day to implement but she came around... the front end was a lot like what SDM is now... not awfully friendly but serviceable... the feature set was extensive and whereas the VPN of the contivity was pretty straight forward, 5520 was a little more complicated... my long term cisco hopes were slowly, very slowly, coming to fruition...
Tuesday, November 1, 2011
a poor man's routing...
routing rudiments...
given: hosts are directly connected, host_A pings host_B
with a nod to lammle, odom, et al
1) host_A creates an echo request for host_B (ICMP)
2) ICMP hands the request to IP, which makes a packet that contains the IP source address, the IP destination address and a protocol field
3) IP determines whether the destination is a local or remote network
4) in this case it is remote, so the packet needs to go to the remote network determined by host_A’s OS (default gateway 172.16.10.1)
5) the MAC address of 172.16.10.1 (E0) is known by host_A. this supposes the arp cache has resolved E0’s IP address to a hardware address. (the output of arp -a will display E0’s MAC address) the packet will be framed by the datalink layer and shipped to the MAC address of E0. hosts only communicate with MAC addresses on the local network
6) if not already resolved, the host sends an arp broadcast to the local network. Upon receipt of the resolution, the host cache’s the MAC address of E0 and encapsulates the packet in a frame with control information.
In both the above cases (hardware address known, hardware address resolved) the framed destination MAC address (E0) and source MAC address (host_A), an ether-type field (network layer IP), the packet, and FCS (frame check sequence which holds the result of a cyclic redundancy check CRC) are shipped to the MAC address of the default gateway, not the MAC address of the remote host
7) the frame thusly prepared, is ready to traverse the physical layer bit by bit
8) at the router, the packet is taken from the frame and off loaded to IP. The remainder of the frame is discarded.
a good place to jump
a good place to jump
my plan...
i am setting up a lab comprised of 3 2610xm routers, a 3550 layer 3 switch, 2 2950 switches and all the cables... basically, a ccnp lab in which i will share lab experiences, lab set ups and anything else i bump into along the way... all things useful that i find towards a certification end, i will post... i will continue to share networking experiences i've had over the past twenty years, as well as any tips or help i may be able to provide... test questions, labs, trial and error, etc...
a word on braindumps... don't waste your time... trust in the materials within your reach... do it legitimately and it will be worth it in the end... there are no shortcuts...
please post any and all comments or suggestions and feel free to email any time... any difficult areas you might have with study materials, test questions, et al...
this will help me in my quest, and hopefully, this will help in yours...
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