Hello,
I have 4 RHEL 5.3 servers (running on HP blades) on my server farm that seem to hang every 2 weeks and needs rebooting to resolve the problem
When this happens the server goes unresponsive to ssh attempted connections and cannot be reached.It can only be reached via the ILO.
before the server goes unresponsive ..sometimes the ssh session hangs for a long long time before the server goes into unresponsive mode.

After cold rebooting via ILO it comes back to normal operation mode .I have looked through the log files thoroughly and found nothing .The other RHEL 5.3 server on this farm dont seem to have that problem and dont have IP tables enabled on them

The only hting i found is that these affected servers have IPtables enabled on them and seem to have high packet rejections..thats all i seem to see in their logs ie system logs /var/log/messages.High volumes of packet rejections in log files because IP tables is turned on

Could it be the IPtables causing this ?.the logs show no indication of any disk ,hardware problem or any other problem. Patching is not an option at the moment.If it IP tables causing this can anyone explain please
Help Please anyone any help would be greatly appreciated

If the affected system states a high degree of rejection, then there is the possible option of brute force attack on your server. I would also suggest you to run the for any rootkit/virus etc on the affected system for any abnormalities

Anirudha0012 thanks but you didnt say how to do it, which commands , etc can you provide more information please, have you experienced this before and if so what exactly did you do...your help would be greatly appreciated. How do you run the rootkit/virus .Thanks

You can run for capture any rootkit from this site - http://www.chkrootkit.org/download/

Download the package and unpack it

Run the daemon as # ./chkrootkit

Also try to check the IP tables rules again