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Revision 6 as of 2005-10-05 10:23:27
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Editor: 194
Comment: Add the URL of ByteSphere's MIBs download page
Revision 7 as of 2005-10-05 17:31:00
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Editor: GuyHarris
Comment: Point to capture originally uploaded here and moved to SampleCaptures.
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XXX - Add example traffic here (as plain text or Ethereal screenshot). attachment:SampleCaptures/b6300a.cap A bunch of GETs and RESPONSEs

Simple Network Management Protocol (SNMP)

SNMP is used to monitor and manage devices on a network.


XXX - add a brief description of SNMP history

Protocol dependencies

Typically, SNMP uses ["UDP"] as its transport protocol. The well known UDP port for SNMP traffic is 161/162. It can also run over ["TCP"], ["Ethernet"], ["IPX"], and other protocols. ["ATM"] uses SNMP as its ["ILMI"] (Integrated Local Management Interface) protocol.

Example traffic

attachment:SampleCaptures/b6300a.cap A bunch of GETs and RESPONSEs


The SNMP dissector is fully functional.

Preference Settings

Ethereal's SNMP protocol preferences let you control the display of the OID in the info column, desegmentation of SNMP over TCP, and which MIB modules to load. Ethereal uses the [ Net-SNMP] or UCD SNMP libraries to resolve OIDs, so you can also configure this behavior using the MIBS environment variable or by editing snmp.conf as described in the [ Net-SNMP Tutorial].

Many network-related MIBs definitions can be downloaded from

Example capture file

XXX - Add a simple example capture file to the SampleCaptures page and link from here. Keep it short, it's also a good idea to gzip it to make it even smaller, as Ethereal can open gzipped files automatically.

Display Filter

A complete list of SNMP display filter fields can be found in the [ display filter reference]

  • Show only the SNMP based traffic:


Capture Filter

You cannot directly filter SNMP protocols while capturing. However, if you know the ["UDP"] ports used (see above), you can filter on that ones.

  • Capture SNMP traffic over the default ports (161 and 162):

     udp port 161 or udp port 162 

SGMP (an ancestor of SNMP):



SNMPv2 (Community based)



SNMP (last edited 2019-11-01 21:48:45 by GuyHarris)