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CRS series and reading the FDB by SNMP?

Thu Jun 22, 2017 2:27 am

I'm trying to map a network with NetXMS and it's problematic with locations that have CRS series units. NetXMS is not able to read the Forwarding DataBase, it complains that the FDB is unavailable
I'm working with existing switches and don't have a lab unit here, so I can't work out if it's a config issue or something else (don't want to go randomly changing things on a production switch). The switches are currently all using isolated customer ports, not sure if that would have any affect on being able to read the FDB? Or if it's just that NetXMS is not looking at the correct SNMP OID to read it

I found this on the NetXMS forums ... -database/ but no answer yet. Appears to work fine if using hardware switching (bridge ports)

Has anyone else had a problem reading the FDB via SNMP on the CRS units? Works fine on all the RB models
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Re: CRS series and reading the FDB by SNMP?

Thu Jul 19, 2018 8:58 am


Sorry in advance if this thread is deemed too old for a reply.

I also have this problem where NetXMS can't read the FDB via SNMP. Our senior tech just tabled the topic again this morning.

Here is what I found out from Victor Kirhenshtein at NetXMS and from Mikrotik support on the issue.

1: You'll see the FDB is obviously working fine on Mikrotik switches. In Winbox, go Switch > FDBs to see the FDB.
2: The FDB is not readable by the SNMP agent on the switch.
3: Victor from NetXMS confirmed their bit is working correctly.
4: I mailed Mikrotik support about it and they said its a known issue and is planned to be fixed in RoS 7.
5: There is no ETA for RoS 7. Mikrotik's usual response in this regard is, its ready when its ready.

Hope this helps and stops others from searching for answers for too long.


Posts: 46
Joined: Mon Oct 17, 2011 4:07 am

Re: CRS series and reading the FDB by SNMP?

Thu Apr 25, 2019 6:57 pm

This appears to now work, at least with the CRS328 I was testing with. With the change to using bridges for most stuff with regards to switches, this is now available in the BRIDGE-MIB (

FDB is

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