Seeking recommendations for the following types of programs:

IP Scanner
Port Scanner
SNMP Discovery

Freeware or shareware is preferred, open source would be an extra plus, for peer review of code.

Thanks.

For SNMP, Download Solarwinds Pro or Engineer's. They pretty much focus on SNMP and are very good at reducing SNMP vulnerabilities.

As for port scanning....I have tons of port scanners and have been meaning to write up an article...I'll take a look at my collection tonight and see if I can recommend a good one.