Can't use community string indexing to get the dot1dTpFdbTable from 2900

Answered Question
Sep 7th, 2009
User Badges:

Hi everyone,

I have a Catalyst 2924 switch, configured with 3 VLANs, I can telnet to that switch and see the mac-address-table by issuing the following command:

Switch#sh mac-address-table

Dynamic Address Count: 5

Secure Address Count: 0

Static Address (User-defined) Count: 0

System Self Address Count: 47

Total MAC addresses: 52

Maximum MAC addresses: 8192

Non-static Address Table:

Destination Address Address Type VLAN Destination Port

------------------- ------------ ---- --------------------

0030.1890.1000 Dynamic 2 FastEthernet0/14

00d0.0648.f41d Dynamic 1 FastEthernet0/2

00d0.0648.f41d Dynamic 2 FastEthernet0/2

00d0.0648.f41d Dynamic 3 FastEthernet0/2

00e0.4c38.2d32 Dynamic 3 FastEthernet0/23

Switch#


Then on a Linux machine with net-snmp installed, I tried to get that mac-address-table with the following SNMP command:

[[email protected] ~]# snmptable -m /usr/share/snmp/mibs/Bridge.mib -c public -v2c 172.16.6.2 .1.3.6.1.2.1.17.4.3

SNMP table: BRIDGE-MIB::dot1dTpFdbTable


dot1dTpFdbAddress dot1dTpFdbPort dot1dTpFdbStatus

0:1:42:9:8a:40 40 self

0:1:42:9:8a:41 40 self

......

0:1:42:9:8a:56 40 self

0:1:42:9:8a:57 40 self

0:1:42:9:8a:58 40 self

0:d0:6:48:f4:1d 14 learned

ff:ff:ff:ff:ff:ff 0 mgmt

As you can see, it only displays the mac-address-table under VLAN1, not the whole mac-address-table, it's said that you have to use community string indexing to get the mac-address-table under each VLAN, but I tried and failed, as indicated by the following output:

[[email protected] ~]# snmptable -m /usr/share/snmp/mibs/Bridge.mib -c [email protected] -v2c 172.16.6.2 .1.3.6.1.2.1.17.4.3

Timeout: No Response from 172.16.6.2

[[email protected] ~]# snmptable -m /usr/share/snmp/mibs/Bridge.mib -c [email protected] -v2c 172.16.6.2 .1.3.6.1.2.1.17.4.3

Timeout: No Response from 172.16.6.2

You have new mail in /var/spool/mail/root

[[email protected] ~]# snmptable -m /usr/share/snmp/mibs/Bridge.mib -c [email protected] -v1 172.16.6.2 .1.3.6.1.2.1.17.4.3

Timeout: No Response from 172.16.6.2

[[email protected] ~]#


The version of our Catalyst 2924 is:

Switch>sh version

Cisco Internetwork Operating System Software

IOS (tm) C2900XL Software (C2900XL-H2S-M), Version 12.0(5.1)XP, MAINTENANCE INTERIM SOFTWARE

Copyright (c) 1986-1999 by cisco Systems, Inc.

Compiled Fri 10-Dec-99 10:57 by cchang

Image text-base: 0x00003000, data-base: 0x002BA814


ROM: Bootstrap program is C2900XL boot loader

......


I tried community string indexing on another Catalyst 4000 L3 switch, and successfully got the mac-address-table of each VLAN, so why can't I get it on the Catalyst 2924 switch? Doesn't Catalyst 2924 switch (or the installed IOS) support community string indexing, or I didn't configure it properly? And is there any other way that I can get the whole mac-address-table on a switch with SNMP commnads?

Correct Answer by Joe Clarke about 7 years 9 months ago

This is known bug CSCdp45404. It is fixed in 12.0(5)XU and higher code. Community string indexing of the dot1dTpFdbTable is the only way to poll the MAC/CAM table with SNMP.

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
Loading.
Correct Answer
Joe Clarke Mon, 09/07/2009 - 10:44
User Badges:
  • Cisco Employee,
  • Hall of Fame,

    Founding Member

This is known bug CSCdp45404. It is fixed in 12.0(5)XU and higher code. Community string indexing of the dot1dTpFdbTable is the only way to poll the MAC/CAM table with SNMP.

xwy5201314 Mon, 09/07/2009 - 23:01
User Badges:

Bravo! jclarke, thanks a lot for your reply, I have resolved the problem after upgrading the IOS of the Catalyst 2900 to :

IOS (tm) C2900XL Software (C2900XL-C3H2S-M), Version 12.0(5)WC17, RELEASE SOFTWARE (fc1)

Copyright (c) 1986-2007 by cisco Systems, Inc.

Compiled Tue 13-Feb-07 15:27 by antonino

Actions

This Discussion