I rebooted my server yesterday. Today three of four clients still function as normal. The client I use cannot access the server. The services used are SSH (PuTTY), Squid, Cups and Webmin. All nothing doing and generally it appears that everything times out.

If I ping the server IP this does not seem to do anything .... I have not waited for more than a few minutes to see if it eventually times out but immediately it just hangs...

I do not understand what is wrong since the other clients are working normally. No changes have been made.

How do I fix this or at least work out what is the problem?

I have just removed a NIC which was installed in the last 24 hours and the system returns to normal.

With the NIC in place I can see it with ifconfig and all appears fine.

May I ask if there is a proper procedure to follow in order to install a NIC on a server?