Scanning for SNMP vulnerabilities
SANS has released a scanning tool called SNMPing which will find SNMP daemons running on a TCP/IP network. It defaults to port 161, but you can enter the port of your choice.
The good news is that it's small and effective. The bad news is that it only runs on WinNT/2K.
You can use TCP dump to log your attempts. You'll find that some devices can be protected with hard-to-guess community names, and that others can't, so get the straight dope on all your devices.
In order to send bulletins about upgrades and bugs to users of the tool, SANS prefers that you e-mail them here to get it. It's automated and takes only a minute to get a reply. We'll just go ahead and not mirror the file, since that actually makes good sense.
Keep in mind that the blackhats undoubtedly have this tool and are happily scanning networks as I type. So use it, see?
That is all. ®