Dartware (some of the former programmers from Dartmouth College) produces a heck of a lot of great Mac Internet software, and has some interesting commercial offerings. MacPing is a free (formerly a $99-$299 commercial product) Ping implementation that supports AppleTalk as well as IP.
MacPing requires a Macintosh computer with a network connection running System 7 or later. For monitoring IP devices, SNMP Watcher requires MacTCP (version 2.0.6 or newer) or Open Transport (version 1.1 or newer).
Can't find what you're looking for? Try a search:
Also, if you have an older Mac, be sure to check out the "Classic" applications page for more options.
Finally, take a look at ALEMIA if you think you know that name of an application, but aren't quite sure.
No, I don't accept reviews anymore for these older applications. With the creation of this page in the Orchard's late 2005 redesign, I only accept reviews for currently-developed applications that work on Mac OS X (or later....whatever that might be!!).