MAC and IP info is missing in Cisco Catalyst switches

Started by r1993r

Decided to scan a couple of new switches today. They are Cisco Catalyst 9300 (L3) and Cisco Catalyst 9200L (L2). I don't think the ARP table or MAC address table is being queried properly, as I can't see any info. When I connect to other models, they results are ok.

Could it be an issue with this switch model? And is there any way to debug or see what's going on?

Cheers,
Darren
SoftPerfect Support forum - Ann avatar image
Ann

Re: MAC and IP info is missing in Cisco Catalyst switches   06 October 2020, 21:19

This suggests the MAC address assignments may not be present in SNMP tables, or are in a format that the Port Mapper did not understand.

Would you be able to run snmpwalk against your switch, dump the complete SNMP tree to a CSV file and send it to us?
SoftPerfect Support forum - Ann avatar image
Ann

Re: MAC and IP info is missing in Cisco Catalyst switches   06 October 2020, 21:39

Thank you for the output file. We have checked it, and this switch seems to only list a few MAC addresses, namely:
.1.3.6.1.2.1.17.4.3.1.1.120.188.26.13.45.175,OctetString, 78 BC 1A 0D 2D AF
.1.3.6.1.2.1.17.4.3.1.1.120.188.26.13.45.176,OctetString, 78 BC 1A 0D 2D B0
.1.3.6.1.2.1.17.4.3.1.1.120.188.26.22.160.175,OctetString, 78 BC 1A 16 A0 AF
.1.3.6.1.2.1.17.4.3.1.1.120.188.26.22.160.176,OctetString, 78 BC 1A 16 A0 B0
These are associated with Port-channel1 and Port-channel2 (#144 and #145). Unfortunately they are the only MAC addresses the switch exposes via SNMP. Though I am not sure if there is an IOS setting affecting that.
I found out what it was. Had to add this command to those switches:
snmp-server group groupname v3 auth context vlan- match prefix
This must be a model- or IOS-specific issue, as I didn't have to do it with other switch models.

Thanks again for you speedy assistance!

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