eigrp network and interface...

in more recent versions of ios code, the routing process can be configured directly on the interface... we know for ipv6 that is the only way... isis was always configured thus,  juniper interfaces as well, so this is not a new concept...
...back to the network statement and russ brings up a fine distinction here:
the network command doesn’t determine what the router will advertise. Instead, the network command determines which interfaces EIGRP will run on...

basically using wildcard masks (instead of simply classful networks) allows you to pick and choose the interfaces to run eigrp on, whether singly, or in ranges...

using a distribute list we can pick and choose the routes we want advertised from anywhere in the eigrp network... note network 1.1.3.0 below:

r2#sh ip route eigrp

Gateway of last resort is not set

      1.0.0.0/24 is subnetted, 3 subnets
D        1.1.1.0 [90/2297856] via 172.16.1.1, 02:36:29, Serial2/0
D        1.1.2.0 [90/2297856] via 172.16.1.1, 02:36:29, Serial2/0
D        1.1.3.0 [90/2297856] via 172.16.1.1, 00:00:09, Serial2/0
      3.0.0.0/24 is subnetted, 1 subnets
D        3.3.3.0 [90/2297856] via 192.168.1.3, 02:36:29, Serial2/1
      10.0.0.0/24 is subnetted, 1 subnets
D        10.1.1.0 [90/2172416] via 192.168.1.3, 02:36:29, Serial2/1
                  [90/2172416] via 172.16.1.1, 02:36:29, Serial2/0


note below how fast eigrp is... as soon as you deny, wham... and then permit, and then the distribute list...

r1(config)#access-list 1 deny 1.1.3.0 0.0.0.255
r1(config)#ac
*Oct 27 16:49:14: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.16.1.2 (Serial2/0) is resync: route configuration changed
*Oct 27 16:49:14: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 10.1.1.3 (FastEthernet0/0) is resync: route configuration changed
r1(config)#access-list 1 permit any
r1(config)#router eigrp 1
r1(config-router)#distrib
*Oct 27 16:49:41: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.16.1.2 (Serial2/0) is resync: route configuration changed
*Oct 27 16:49:41: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 10.1.1.3 (FastEthernet0/0) is resync: route configuration changed
r1(config-router)#distribute-list 1 out
r1(config-router)#
*Oct 27 16:49:59: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 172.16.1.2 (Serial2/0) is resync: route configuration changed
*Oct 27 16:49:59: %DUAL-5-NBRCHANGE: EIGRP-IPv4 1: Neighbor 10.1.1.3 (FastEthernet0/0) is resync: route configuration changed
r1(config-router)#

r2#sh ip route eigrp

Gateway of last resort is not set

      1.0.0.0/24 is subnetted, 2 subnets
D        1.1.1.0 [90/2297856] via 172.16.1.1, 00:00:48, Serial2/0
D        1.1.2.0 [90/2297856] via 172.16.1.1, 00:00:48, Serial2/0
      3.0.0.0/24 is subnetted, 1 subnets
D        3.3.3.0 [90/2297856] via 192.168.1.3, 00:00:48, Serial2/1
      10.0.0.0/24 is subnetted, 1 subnets
D        10.1.1.0 [90/2172416] via 192.168.1.3, 00:00:48, Serial2/1
                  [90/2172416] via 172.16.1.1, 00:00:48, Serial2/0
r2#

all gone...

you can also block per interface in the eigrp process with:

distribute-list 1 out s2/0

but be careful with this one, if there's an alternate route... look at the path and the rd closely for 1.1.3.0 and compare it to above...

r2#sh ip route eigrp

Gateway of last resort is not set

      1.0.0.0/24 is subnetted, 3 subnets
D        1.1.1.0 [90/2297856] via 172.16.1.1, 00:09:06, Serial2/0
D        1.1.2.0 [90/2297856] via 172.16.1.1, 00:09:06, Serial2/0
D        1.1.3.0 [90/2300416] via 192.168.1.3, 00:00:16, Serial2/1
      3.0.0.0/24 is subnetted, 1 subnets
D        3.3.3.0 [90/2297856] via 192.168.1.3, 00:09:06, Serial2/1
      10.0.0.0/24 is subnetted, 1 subnets
D        10.1.1.0 [90/2172416] via 192.168.1.3, 00:09:06, Serial2/1
                  [90/2172416] via 172.16.1.1, 00:09:06, Serial2/0

it took the long way around...