After I've applied fsck command on the hard disk of my Redhat 6.2 system, some services go down on the server such as TELNET,POP3, SMTP, and NAME DAEMON.
I recover that by rebooting the server(which is an improper way).

Any way to solve that?

I don't follow... you run fsck (on what file system?) and some of your services stop?

You should just be able to restart them on the command line if they're just stopped, but I would be wondering more about what stopped them.

Jamie...

I didn't say "the services stopped" , I said "the services go down". That means although the services (POP3, sendmail, and named) are running, but when I connect to the server from a remote host, then the connection TIMEOUT.

Even I can not TELNET the server but I can ping to it!!!

Then a I reboot the machine and it goes normal again (i,e, the services run normally) and I can TELNET the server.

This problem was not exsiting until I've run fsck on the server's file system.

Which implies that this kind of system misbehave is related to either file system or memory management(as I think)!

And my question is if there is a way to prevent and recover that kind system misbehave????

Although I would consider fsck crashing your network a serious problem, you could try restarting the acual network. I beleive the scripts to do that are in /etc/sysconfig/network. It sounds like it is your network going down, not the services. I know you said that you can ping the server, but that doesn't necessarily mean their is'nt a network problem.

What I think jharris was getting at is what filesystem are you running fsck on. (i.e. what partition and what is mounted on that partition.) See if you can isolate what partition is causing the problem.