When I installed Fedora 10 on my office-machine, I configured the network-manager to connect to the internet thru' proxy server. It worked but stopped after a few days and again started working properly, but now it is again not working.
Also, in earlier versions of Fedora I could also simultaneously connect to other unix m/c in the office. But now I cannot do that. The process of connecting which was so easy in Fedora 6 seems to be very difficult in Fedora 10.
I need help at the earliest.
Thanks a lot for whatever help one would be able to provide.

You need to give us more information.

Does your network have a local DHCP server? That is, did you get an IP address automatically assigned (DHCP), or did a human tell you an IP and you typed it in (not DHCP)?

Most office LANs use NAT, meaning your machine is assigned a local IP address, like 192.168.x.x or 10.x.x.x or 172.16.x.x, which gets translated to a global IP for external communications. Does your LAN use NAT?

Can you show the output of these commands? (You can X-out IPs and/or HWaddr if you are concerned.)