Hello vamsiathota There is a known issue of NICs going offline and not functioning after OMSA has been installed. It is specific to Broadcom NICs/LOMs running old firmware. It has not been noticed with version 7.1 of OMSA, but it may still be relevant.  
Hello, I have installed Open Manage System Administrator on 2 Domain controller and both of them have lost connectivity immediately after install. We tried rebooting them and both of them wouldn't connect to the Internet after the reboot. I had to disable and re enable the network adapter to make them work. I tried updating the NIC with the latest driver but it did not help. This is a major issue with 2 domain controllers down. :( PowerEdge T300 - Win Server 2003 Standard PowerEdge R300 - Win Server 2008 Standard Any help on this issue will be greatly appreciated.
Domain Controller - looses connectivity on reboot after OMSA install