Linux NFS syn_sent

I have a web server farm that mounts their docroot via NFSv3 over TCP
across 2 layers of firewalls (Yeah I know Client request) to an EMC
Ceterra? NAS box, what's happening is Apache intermintely hangs and
spikes the CPU on a server at this point your unable to
shutdown/restart apache or even attach via gdb or run strace its hung
waiting for some sort of request or i/o after a while this happens
across all CPU's and the box is pretty much hosed could be anywhere
from 1 hour to 1 week, after doing some trouble shooting, I noticed my
apache servers all have seem to have the following session in netstat
"syn_sent" which refuses to timeout or maybe its just constantly going
into a "syn_sent" state i'm unable to tell if its timing out this is to
port 2049 NFS to the NAS box, after looking through the firewall logs
i'm seeing lots of dropped packets, I'm also noticing that the
nfs client is using the same src ports 798,799,800 over and over so
basically my firewall (checkpoint) is seeing the client trying to
create a new session that is already opened and dropping it, the
firewall is statefull, anyone has any idea how I could trouble shoot
this, maybe some way I can have the Linux nfs client behave like
Solaris?

If it make any difference this is Redhat AS kernel 2.4.21-32.0.1



rodrick.brown@gmail.com