Linux Server Leaving the Network

[Abhishek Aggarwal]

HI Guys 
I am facing an issue in my organization. the issue is that the linux servers are leaving the network and  i had checked all the logs there is no such error which is mentioned in /var/log/messages/. kindly help me out as this issue has caused a lot of problem in my organization. Will be waiting for your reply 
 
Thanks in Advance 

Abhishek
RHCSS,CCNP