SNMP - dot1dTpFdbAddress doesn't work properly on 3500XL

[patpee_NL]

Hi!

I want to use SNMP to get all the port and MAC-information from the switches in our network. I've been looking at the Cisco documentation at their site and found this:

http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a00801c9199.shtml

In this document is everything covered we need to know. But... we are experiencing some 'troubles'. On our 4506-switch (CatOS 8.1), the following line works flawless and shows all the MAC-adresses 'connected' to VLAN2.

snmpwalk 10.1.17.1 public@2 .1.3.6.1.2.1.17.4.3.1.1

But now the problem: if I execute the same line with the IP-address of the 3500XL (it's a 3524XL to be exact, with IOS 12.0(5.1)XP), then I get a timeout.

If I use:

snmpwalk 10.1.17.2 public .1.3.6.1.2.1.17.4.3.1.1

then there is some output but it's not what I need. It only shows the System's Self MAC-addresses and two out of three dynamic MAC-adresses of VLAN1. I checked it in the switch with 'sh mac-adress-table dynamic' and that showed a list that was much bigger and without all those System's Self MAC-addresses.

What could be the solution? My thoughts were that maybe the '@' isn't parsed well, but then it also shouldn't work at the 4506 switch.

Or maybe it's the IOS version? Although the version mentioned in the document i've linked to is older...

BTW: I'm using SuSe 8.0 with UCD-SNMP 4.3, if you might need that info.

[patpee_NL]

After some testing with some other 3500XL switches around here, it appears that the problem is caused by the firmware.

If i run the command "snmpwalk 10.1.17.3 public@2 .1.3.6.1.2.1.17.4.3.1.1" on a switch with IOS 12.0(5.2)XU then it shows some output.

But if I run "snmpwalk 10.1.17.3 public@ .1.3.6.1.2.1.17.4.3.1.1" it shows the same output, which includes the System's Self addresses again. Which it shouldn't.

Probably this is solved in a newer IOS, but we don't have that here so we'll have to do it with this.

[#3]

I have the exact same problem here with 3500XL switches. I tried putting in the community public@15 (which is the VLAN that is mostly used on the switch), and I can walk now with this community string, and I get mostly the same but a few new ones too. But all of them are from the Gigabit uplinks, none of the local ports. Switch has IOS 12.0(5.1)XP.

[dave.keith]

On our 12.0(5.4)WC1 3500XL units, a walk starting at .1.3.6.1.2.1.17.4.3.1 lists a bunch of MACs, then the corrisponding ports, then the corrisponding status (dot1dTpFdbStatus), which indicates either 'learned' or 'self', plus one 'mgmt' entry (we have no perminant entries).

Dave