RHEL4 Network problem

I have recently been experiencing a very strange problem with a different RHEL 4 server, providing a number of different services. Basically, it appears that packets are occasionally delayed or
dropped, apparently randomly.

plz help me

Hi Sateesh,

It'd be a bit more helpful if you could be a little more specific about your problem.

Please explain.

Thank you for your help

i have RHEL4 AS, it is a mail server .
in this server only bellow services are running.

1 qmail(smtp) (it is downloaded from qmailrocks.org)
2 pop3
3 imap
4 clamav
5 spamd
6 webmin
7 ssh
8 http/https
9 qmailscanner

advanced power options are disabled
selinux is disabled
iptables also disabled
ipv6 is also disabled

the server is not responding randomly.(all services, ping request timed out) after some time it is comming back normally.
when the server is not responding, at that time server is not hanging it is responding each and every command wery well.

plz advise me