authentication...

i hate authentication... no wait, i LOVE authentication...

the books say you can either set up authentication per area, or per interface with ospf... i beg to differ... perhaps it's older code, not sure, either way it's a pain in the ass...

r1#debug ip ospf packet
OSPF packet debugging is on
r1#
*Nov  5 17:15:51.342: OSPF-1 PAK  : rcv. v:2 t:1 l:48 rid:10.1.40.1 aid:0.0.0.0 chk:3542 aut:0 auk: from FastEthernet0/0

debugging the packets is a good way to check if the authentication is working, note above our authorization code is 0 (aut:0)

place authentication on the neighbors using plain text...

r1(config)#int f0/0
r1(config-if)#ip ospf authentication-key cisco

r2(config-if)#ip ospf authentication-key cisco
r2(config-if)#

no help with that shit...

r1#
*Nov  5 17:21:42.042: OSPF-1 PAK  : rcv. v:2 t:1 l:48 rid:10.1.40.1 aid:0.0.0.0 chk:3542 aut:0 auk: from FastEthernet0/0

now turn it on for the area on each router...

r2(config-if)#router ospf 1
r2(config-router)#area 0 authentication

r1#
*Nov  5 17:26:20.030: OSPF-1 PAK  : rcv. v:2 t:1 l:48 rid:10.1.40.1 aid:0.0.0.0 chk:3541 aut:1 auk: from FastEthernet0/0

now it works... same for  md5... arghh...

r1#sh ip ospf int f0/0
FastEthernet0/0 is up, line protocol is up
  Internet Address 192.168.1.1/24, Area 0, Attached via Network Statement
  Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
  Topology-MTID    Cost    Disabled    Shutdown      Topology Name
        0           1         no          no            Base
  Transmit Delay is 1 sec, State BDR, Priority 1
  Designated Router (ID) 10.1.40.1, Interface address 192.168.1.2
  Backup Designated router (ID) 1.1.1.1, Interface address 192.168.1.1
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:02
  Supports Link-local Signaling (LLS)
  Cisco NSF helper support enabled
  IETF NSF helper support enabled
  Index 1/1, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 10.1.40.1  (Designated Router)
  Suppress hello for 0 neighbor(s)
  Simple password authentication enabled


turn area authentication back off...

r1#sh ip ospf inte f0/0
FastEthernet0/0 is up, line protocol is up
  Internet Address 192.168.1.1/24, Area 0, Attached via Network Statement
  Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
  Topology-MTID    Cost    Disabled    Shutdown      Topology Name
        0           1         no          no            Base
  Transmit Delay is 1 sec, State BDR, Priority 1
  Designated Router (ID) 10.1.40.1, Interface address 192.168.1.2
  Backup Designated router (ID) 1.1.1.1, Interface address 192.168.1.1
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:01
  Supports Link-local Signaling (LLS)
  Cisco NSF helper support enabled
  IETF NSF helper support enabled
  Index 1/1, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 10.1.40.1  (Designated Router)
  Suppress hello for 0 neighbor(s)

all gone, but look at f0/0...

r1#sh run int f0/0
Building configuration...

Current configuration : 151 bytes
!
interface FastEthernet0/0
 ip address 192.168.1.1 255.255.255.0
 ip ospf authentication-key cisco
 speed auto
 duplex auto
end

whoops...  i love expected behaviors that are unexpected...