You can always enable back the built-in MS Messenger service. It is still there. But need to setup group policy for security.
Congrats Starvinmarvin re passing Gibson ShieldsUP test.
I think your firewall is on and it binds the port to the program.
IP Messenger does open port 2xxx (not to expose it here ). I find Windows firewall binds the port to it so the port is close to other programs.
I also tested portable Lan Messenger. It opens port 5xxxx as well. Win7 firewall detected it and locked down the port, and only opens the port to Lan Messenger.
I subsequently did gpedit (group policy) to verify and further tightened the security. That is, bind the source-port and destination-port to Lan Messenger (or IP Messenger). Also set protocols to TCP and UDP only. Then set profile to custom: allow local LAN address range only (e.g. 192.168.0-255). Now Lan/IP Messenger can only communicate within the local network.
A lot more secure that way but still does not prevent spoofing + penetration through router/NAT. An additional router/NAT in series does help though.
The best security (for localnet messenger service, that is) is not to use TCP/IP protocol with messenger. That absolutely isolates its traffic from Internet. In XP and older days, we can bind NetBeui to local and Messenger services. It is strictly local protocol, totally contained inside localnet. Too bad Win7 and up removes it (and does not allow it).
Yeah, NetBeui is dirty (communication-wise!), chatty, and noisy. Actually it is more efficient than TCP/IP! TCP/IP is for low reliability medium (world wide web). NetBeui is for reliable medium (reliable network wiring). It takes up cable bandwidth alright. But when does a home network has 150 PCs on it? It is perfect for consumer home use. Easy to setup. Just works. And secure (not talking to 'outsiders').
i guess you can't be too careful. However, during the eight years we've lived here we've never had our wireless network or LAN hacked. We've used a Comcast modem which we dumped when they jacked up the rental cost from $3 to $7 per month. Bought a Motorola for $89 which paid for itself in about 1 year. Have used 3 different routers, all with a WPA-2 security passphrase more than 20 characters; currently it's a Western Digital MyNet N900 (with WPS turned off). Various anti-virus progs have included AVG and Avira, and for the last 4 years we're using Avast free edition. We see the occasional Avast popup malware alert for some website we clicked on ostensibly to read a news story. Once in a while i run a Boot-time Scan or MalwareBytes scan or a rootkit scan (Panda, maybe?) when i'm bored, but nothing ever turns up. For us, the only real threat of a cyber attack is our own stupidity and, so far, that has not proved damaging! We store some stuff on Dropbox/Skydrive, but it's all encrypted before we upload and there's no sensitive personal or financial info there anyway. We shop online but choose the option for the website NOT to save our payment information and frequently use Paypal anyway. Passwords are generally unique and are handled by a password manager and not by the browser. You can keep piling on extra layers of security at every turn but what we have seems sufficient for our needs. As for the tiny IP Messenger program ... well, it works great and - what happens on the LAN stays on the LAN.