Unexpected behavior with 3560 and snmp.

• February 18, 2010
• Technology  
• 3560  
• snmp  

Yesterday evening I was playing around some more with SNMP and sending different traps.

I was mainly playing around with my 3560 switches. They were running IOS 12.2(35)SE1 (IPServices). What struck me as odd was the behavior when configuring multiple snmp hosts.

Even though i configured only some traps to be sent to certain hosts, when it would generate any one of them, it would send out snmp traps to all hosts! At first i thought i was loosing it, but then i decided to try it out on my 2950. On this platform it worked as advertised (and documented by Cisco). Just to make sure, i performed the same test on a 3550. Worked perfectly as well. This was certainly pointing toward an IOS bug in that release.

Sure enough, today I got a chance to run a newer codebase (12.2(53)SE IPservices), and with this, a 3560 worked just fine again. So dont take anything for granted 🙂

I used two simple debug commands:

“debug snmp packet” (See what hosts the router/switch is preparing the snmp traps for).

“debug ip packet” (actually verify that the router/switch sends these out).