If you are going to run real world DNS, you need to know the already mentioned DNS and Bind
backwards and forwards. Also, I trust that you know 192.168.0.1 is not a publicly available address?
The TTL can safely bee lowered to 3600, which is one hour. I have never seen
@ 7d IN NS ns1.domain.com.
before in a zonefile. Not sure if that will work or not. The accepted method for identifying nameservers is:
ns1 7200 IN A 220.127.116.11
Why people think they should hide their addresses when asking for help with zonefiles is rediculous. We could have helped easier if we could have tested the nameserver itself, and the "domain.com" and 192.168.0.1 just make that impossible.