How can I monitor network in CentOS .5.5 , my application refuse to read sockets

Hi
I have wired problem with one of my applications (servers ) , its suddenly starts to read socket and before it written back , the connection is closed
this is what I see in my logs . is there any took in Linux centos that lets me see what is happening in this time frame ?

A packet sniffer likes tcpdump or wireshark is quite handy in such situations.