Wireshark-users: [Wireshark-users] Malformed Packet - SNMP Trap

From: Rexford Park <rex.park@xxxxxx>
Date: Thu, 29 Aug 2013 21:19:42 +0000 (GMT)
I've been working on an SNMP v2c Agent library for the Arduino platform and hit a bit of a roadblock. So far the library works fine on messages that are under 172 bytes long. Once the messages hit 172 bytes they aren't picked up by SNMP Managers and Wireshark lists them as Malformed Packets.

I'm hoping I can find someone here that is more familiar with SNMP and can help me figure out what exactly is wrong with the packet so that I can dig into my code and fix the issue. Is there a way to get Wireshark to tell me where the packet has failed?

Wireshark Output of a malformed trap:

0000   a8 20 66 28 f1 69 de ad be ef fe ee 08 00 45 00
0010   00 9e 00 03 40 00 80 11 e3 8e 0a 23 01 3d 0a 23
0020   01 3b 00 a1 00 a2 00 8a 75 15 30 80 02 01 01 04
0030   06 70 75 62 6c 69 63 a7 73 02 04 00 00 00 02 02
0040   01 00 02 01 00 30 65 30 10 06 08 2b 06 01 02 01
0050   01 03 00 43 04 00 00 09 c5 30 19 06 0a 2b 06 01
0060   06 03 01 01 04 01 00 06 0b 2b 06 01 04 01 82 99
0070   3b 01 00 01 30 10 06 0b 2b 06 01 04 01 82 99 3b
0080   01 01 01 02 01 16 30 24 06 0b 2b 06 01 04 01 82
0090   99 3b 01 01 02 04 15 31 32 33 34 35 36 37 38 39
00a0   30 31 32 33 34 35 36 37 38 39 30 31

Thanks