Thank you for your reply.
I have used an "Automatic" option. So ESXi generated MAC address automatically.
I installed 2 systems from the same ISO. One with X Windows, another without one. After VMware Tools installation the one with X windows showed IP just fine, whereas the one without X windows was not. Same VM configuration. Networking is also same. I am able to ping internal and external IPs with both. So I am just wondering, if there is some kind of a module not installed on Linux without GUI. And if that is true, then how can I add one.