EIGRP Neighborship on sub interfaces

Hi Team,

I am trying to form EIGRP neighborship between a Cisco Router ( over sub interfaces) and two ASA in context. ASA-C1 is able to form the neighborship with both R9 and R8. However, ASA-C2 is only able to form neighborship with R8.
Can ASA-C2 also form neighborship with R9 ?
Note: ASA-C1/C2 can ping both R9 sub-interfaces.


interface GigabitEthernet2
no ip address
negotiation auto
interface GigabitEthernet2.1
encapsulation dot1Q 6
ip address 5.X.6.9
interface GigabitEthernet2.2
encapsulation dot1Q 7
ip address 5.X.7.9

router eigrp 1
network 5.X.6.0
network 5.X.7.0
redistribute static

Can you please help ?

Hello Dhruv

When you work with contexts in an ASA, you must make sure that you are assigning the correct interfaces to the correct context. In this case, you are creating a single physical connection between R9 and the physical ASA, and you are using subinterfaces on that link. In essence, you are creating a trunk.

It is not possible to assign a single physical interface to multiple contexts. However, you can assign subinterfaces on the same interface to different contexts. You must make sure that on the ASA you have assigned the correct subinterfaces to the correct context, and that the source of your pings is indeed the subinterface of the context in question.

When you configure those subinterfaces, there are several limitations which are described further in this Cisco documentation:

Hopefully, this information will help you to further troubleshoot your specific issue. If you need further help, can you share with us your interface configurations within the two contexts of the ASA?

I hope this has been helpful!