Cannot FTP or ping. Traceroute does work. Something has obviously changed in configurations somewhere in the systems for this server to not connect to offsite servers like before. Our other one has no problem connecting to the same IP address. This is not a DHCP system and the IP address has not changed.

So on those hosts which you connect to, can you resolve the IP addresses of these two servers? This is just a tangent but I've found that some sites are set up to try reverse DNS, and take a lot of time if it doesn't work. ident would be another thing to look for -- do you have an ident daemon running on one host, but not on the other?

You are saying you can ping by IP address from the OK host, but not from the broken one? That would rule out anything like this. But then you shouldn't be able to traceroute either ...?

I cannot ping from either which is not unusual.
Working Server:Cannot ping, can telnet, can ftp, can traceroute
Server having trouble:Cannot ping, cannot telnet, cannot ftp, can traceroute. The connection problem is only on certain IP addresses, not all on the troubled server only.

How can i know who has telneted to my system and made some changes...?

i want know the ip of user who has telneted before

The fact that traceroute works would seem to suggest that you have a working route and a working network card. I continue to ask: can you resolve the IP address of both servers from the hosts which refuse access from one but not from the other (because that's what I think is going on here)?

this is a new problem. please open a new thread for this!

What exactly do you mean by resolving the IP address? I can't see how an IP conflict is a possibility since I can telnet and ftp to some but not all the hosts from this server. And thank you for being patient with me on all of this.