eigrp and multicasts...

given this frame switch scenario...

other than wireshark, the best way i've found to see the multicast traffic is using debug ip packet...

r2#
*Sep 14 05:55:11: IP: s=10.1.1.1 (Serial1/0), d=224.0.0.10, len 60, rcvd 0
*Sep 14 05:55:11: IP: s=10.1.1.1 (Serial1/0), d=224.0.0.10, len 60, input feature, packet consumed, MCI Check(85), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE
r2#
*Sep 14 05:55:21: IP: s=10.1.1.3 (Serial1/0), d=224.0.0.10, len 60, rcvd 0
*Sep 14 05:55:21: IP: s=10.1.1.3 (Serial1/0), d=224.0.0.10, len 60, input feature, packet consumed, MCI Check(85), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE

to make the hello's unicast, add the neighbor statement to both sides of a link...

in this case the unfortunate consequence is we lose r3, if it has not been statically added...

r2#sh ip route eigrp

Gateway of last resort is not set

      1.0.0.0/24 is subnetted, 1 subnets
D        1.1.1.0 [90/2297856] via 10.1.1.1, 00:05:29, Serial1/0
r2#
*Sep 14 06:08:14: IP: s=10.1.1.1 (Serial1/0), d=10.1.1.2, len 60, rcvd 0
*Sep 14 06:08:14: IP: s=10.1.1.1 (Serial1/0), d=10.1.1.2, len 60, input feature, packet consumed, MCI Check(85), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE
r2#
*Sep 14 06:08:19: IP: s=10.1.1.2 (local), d=10.1.1.1 (Serial1/0), len 60, sending
*Sep 14 06:08:19: IP: s=10.1.1.2 (local), d=10.1.1.1 (Serial1/0), len 60, sending full packet
r2#
*Sep 14 06:08:22: IP: s=10.1.1.3 (Serial1/0), d=224.0.0.10, len 60, rcvd 0
*Sep 14 06:08:22: IP: s=10.1.1.3 (Serial1/0), d=224.0.0.10, len 60, input feature, packet consumed, MCI Check(85), rtype 0, forus FALSE, sendself FALSE, mtu 0, fwdchk FALSE

note the unicasts bewteen r1 and r2, and yet multicasts from r3, but no r3 route...

it's a different landscape...

the route table is restored when all ip's are referenced as neighbors...

r2#sh ip route eigrp

Gateway of last resort is not set

      1.0.0.0/24 is subnetted, 1 subnets
D        1.1.1.0 [90/2297856] via 10.1.1.1, 00:19:15, Serial1/0
      3.0.0.0/24 is subnetted, 1 subnets
D        3.3.3.0 [90/2297856] via 10.1.1.3, 00:04:20, Serial1/0

and wireshark reports all neighbors unicast...

that requires a neighbor statement for every ip in the topology...

r3#sh run | beg router
router eigrp 1
 network 3.0.0.0
 network 10.0.0.0
 neighbor 10.1.1.2 Serial1/0
 neighbor 10.1.1.1 Serial1/0

and of course, wendell covers this in the ocg...

Caveat:  When Using EIGRP Static Neighbors IOS changes how it processes EIGRP packets on any interface referenced by an EIGRP neighbor command. Keeping in mind the design goal for this feature—to reduce multiasts

IOS disables all EIGRP multicast packet processing on an interface when an EIGRP neighbor command has been configured.

be very afraid...