The HL7 Inspector project has moved to Bitbucket.
https://bitbucket.org/crambow/hl7inspector
All new releases can be found there.
The web-based version can still be found at www.hl7inspector.com
NetworkTools has 2 components: A protocol analyzer which plays a TCP client or server or pipeline, which sits between a client and server and shows how they communicate. A port scanner can scan a range of IP addresses and ports. See screenshots.
httptrace - TCP/HTTP trace utility (for Java or Win32/jview.exe)
Listens on a TCP/IP port, redirects data to another port and writes traces.
Several options (search for patterns, ...).