Thanks Mr Phoenix for valuable replys, My problem is solved now, its running fine.
I'm glad you've fixed it.
Originally Posted by Radhakishan
I have not changed hosts file and even not installed DNS.
Your hosts file does need to be changed otheriwse it will cause you problems. As you're behind a NAT router then you will need valid DNS A & MX records, if you don't have them set-up on a LAN DNS server you will need them.