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SNMP, VRFs, Interfaces, and IP Addresses

mfarrenkopf
Level 1
Level 1

The ipAddrTable section of MIB-II was written before VRFs existed (or likely had ever been conceived of).  As a result, if more than one interface has the same IP address, it only returns one ifIndex (presumably the highest).

We have a large deployment going on right now using multiple VRFs in a L3 access design.  This design uses the same /30 subnets for uplinks between each VRF.  (For example, 10.125.251.32/30 for uplink A in MAIN, then 10.125.251.32/30 for uplink A in PWIRED, etc.)  Because they're in different VRFs, this is a valid configuration.  Unfortunately, ipAdEntIfIndex can only return one ifIndex value.  So if I'm tracking an EIGRP relationship in VRF MAIN and the interface in VRF PWIRED has the highest ifIndex value, then I only see my IP address on the ifIndex pointing to the PWIRED VRF and I have no way to associate my IP address on the interface in the MAIN VRF.

I've looked at the CISCO-IP-IF-MIB to deal with this, but it doesn't look like there's much support for it.  Most of our installed access layer consists of Cisco 3750s, with 3650s and 3850s coming into the fold.  None of them support that MIB.  ("None of them support" meaning I get "No Such Object available on this agent at this OID" when I walk that part of the MIB.)

Any ideas on a MIB that I can use to get the IP addresses assigned to each interface regardless of whether or not it's the same IP address on different interfaces?

Thank you!

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