SNMP message response source address different to the request destination address.

Hi,

I've got an issue with a certain piece of hardware that I've been dealing with for a few years but I'd like to finally get to a solution.

We have a collection of (Aviat CTR8540) nodes in our network that respond to SNMP requests on different interfaces to what was polled.

i.e.
Node has 3 IP interfaces.

Loopback interface: 192.168.1.1
Physical Interface 1: 10.1.1.1
Physical Interface 2: 10.1.2.1

Orion manages the node with loopback address 192.168.1.1.
Orion sends SNMP request to 192.168.1.1
Node receives request, processes and then sends response from interface that is closest to shortest path to NMS (Determined by OSPF)
Solarwinds receives the SNMP response but disregards presumably because its from a different address.

I believe this is a problem with the SNMP process implemented by the Vendor and have raised this with them twice but they've offered no solution, they tell me that their proprietary NMS deals with this and that I should configure our NMS to do the same thing. I assume they have a unique string in each SNMP request which they look for in the response to tie back to the node...Maybe?

I'm trying to identify if the Vendor is complying with the relevant SNMP standards.

I'm not sure what the best RFC standard to look at is but RFC 1157 states

"The protocol entity then performs a rudimentary parse on
the ASN.1 object returned from the authentication service
to build an ASN.1 object corresponding to an ASN.1 PDUs
object.  If the parse fails, it discards the datagram and
performs no further actions.  Otherwise, using the named
SNMP community, the appropriate profile is selected, and
the PDU is processed accordingly.  If, as a result of
this processing, a message is returned then the source
transport address that the response message is sent from
shall be identical to the destination transport address
that the original request message was sent to."

Can someone provide any information in regard to this?

Is this a problem with the vendors implementation? If so I'd like to be able to point at a standard to give them an incentive to provide a solution.

Alternatively, is there a simple hidden setting somewhere in Orion to resolve this?

Any input would be appreciated. Thanks

Any input would be appreciated.