I have 5 computers running with IP address 192.168.x.x. Subnet mask: 255.255.255.0. While doing the network checking for the TCP/IP communication, I ping to respective com, and are succeccfully with all the reply to respective com. But on the next day, The 5 computers are lossing communication and unable to ping to each other and loop back and local IP address (itself). I suspect maybe it because I have installs firewall software that causes the IP address: 127.0.0.1 by mistaken or maybe have been configuration by auto setting from firewall software? Kindly advise. Thank you :rolleyes:

What kind?
Did you have all the computers working before this install?
What are you using to connect the computers?

Thank for your reply. I have removed the program, and able to get the transmissions going now

Question: how to keep away virus from going around the network with low cost or no cost? By setting some of the ports access to disable, and yet able to use Internet and email. Pls advise. Thank you.

What virus are you referring to, or is this just in general?

It sounds like you have a router, which is using NAT that is considered a hardware firewall.

Make sure you are using all the current patches Microsoft develops.

You can use this nifty tool designed by Microsoft to check your network for vulnerabilities, and other things.

information:
http://www.microsoft.com/technet/tre...s/mbsahome.asp

download:
http://download.microsoft.com/downlo.../mbsasetup.msi

Have fun