network connections are getting stuck in ESTABISHED state

Greetings folks!

I am connecting to various FTP and HTTP sevices from a linux machine
(RH Enterprise kernel 2.4.20-8). Ftp in -i mode is used from bash
scripts as well as Perl LWP::Simple get() is utilized to fetch URLs.
There is a CISCO NAT firewall between the box and the outer space. The
connections are made to different target IPs.

What happens is that often network connections are permanently stuck
in ESTABLISHED state. ps shows tonns of processes hanging out there
waiting for their network calls to die out. The scripts are run from
cron. It's nothing too comlex, just go there, grab an URL and parse it
out.

Do you have any ideas?

Cheers!