EIGRP not passing through trunk ports

[lucas.shelton1]

We are setting up EIGRP for gateway failover to a redundant data center and I'm having issues getting EIGRP (or OSPF for that matter) to form an adjacency.  I've attached diagram of our setup but a brief description below:

Campus LAN eventually hits a Nexus 5596, trunked to a 3560 that serves as the default gateway.  On the 3560 there's a Int VLAN 7 10.7.0.254.  This 3560's DG is a Palo Alto, which eventually hits the internet.  For redundancy we have a fiber link from the 3560 to an offsite DC that hits another 5596, then another 3560 with an Int VLAN 8 10.8.0.254.  On both 5596's there is also an Int VLAN 999 with 192.168.1.1 & 192.168.1.2.  I can PING the Int VLAN 999 of the other 3560 on each switch.  However they are not forming an adjacency.  Is something configured incorrectly with my trunks?  The VLAN's are present on each 5596 & 3560.  See diagram to fully understand.

[lucas.shelton1]

Turned debugging on both switches and nada.  No output.  EIGRP is turned on, but doesn't look like its doing anything.

[Richard Burts]

Is multicast enabled on the Nexus?

What do you get as output to the command show ip eigrp interface on the Nexus?

HTH

Rick

[lucas.shelton1]

XXXX5596# show ip eigrp interfaces
IP-EIGRP interfaces for process 1 VRF default

Xmit Queue Mean Pacing Time Multicast Pending
Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes
Vlan7 0 0/0 0 0/0 0 0
Hello interval is 5 sec
Holdtime interval is 15 sec
Next xmit serial <none>
Un/reliable mcasts: 0/0 Un/reliable ucasts: 0/0
Mcast exceptions: 0 CR packets: 0 ACKs suppressed: 0
Retransmissions sent: 0 Out-of-sequence rcvd: 0
Authentication mode is not set
Use multicast
Classic/wide metric peers: 0/0
Vlan8 0 0/0 0 0/0 0 0
Hello interval is 5 sec
Holdtime interval is 15 sec
Next xmit serial <none>
Un/reliable mcasts: 0/0 Un/reliable ucasts: 0/0
Mcast exceptions: 0 CR packets: 0 ACKs suppressed: 0
Retransmissions sent: 0 Out-of-sequence rcvd: 0
Authentication mode is not set
Use multicast
Classic/wide metric peers: 0/0

[lucas.shelton1]

That output came through all funky, see attached screenshot for show ip eigrp interfaces command.

[lucas.shelton1]

Looks like it is a VIRL bug.  In our live environment I trunked a 3560G off the 5596, created the VLAN interfaces and enabled eigrp on the VLAN interface of the 5596, also created eigrp instance on the 3560.  They formed an adjacency just fine and exchanged routes.

[lucas.shelton1]

Jon,

I've got it setup and partially working.  I've redistributed the static routes however if I shut down the interface on the 3560 facing the Palo Alto the route doesn't get removed from the routing table,thus still advertising that route as reachable.

I thought it removed that route.

[Richard Burts]

I believe that you are encountering a fairly common issue when dealing with static routes using Ethernet interfaces. The logic in IOS will remove a static route when the interface associated with the route goes into the line protocol down state. That works well for things like point to point serial interfaces which do go line protocol down if they lose communication over the interface. But with Ethernet interfaces there are many circumstances where you have lost communication over the interface but the interface remains in the line protocol up state. The solution to this is frequently to use some variation of IP SLA/track to control the static route and to remove it if communication is lost over that interface.

HTH

Rick

[Jon Marshall]

Rick

If the link is a direct link between the two devices then if one end goes down so should the other one.

If there is an intermediate device then yes I agree with what you say but there isn't here as far as I know.

Jon

[Jon Marshall]

If the route is pointing to firewall as the next hop and you shut the interface down on the 3560 it should definitely remove the route.

Rick is right about some setups but that is why I asked if this was a direct connection between the 3560 and the firewall.

Jon