Greg's got some good points. Recently, we had to call the ISP that serves two of our client because they had blanket-blocked all inbound traffic on ports 80 and 25. Now, these were business accounts, but they simply shut the whole system table down piecemeal and brought the businesses back up individually as we called them. If they find out, and it is against your TOS, you could be up a creek.
That said, DNS is a tad tricky, but nowhere near impossible, else the 'Net would not exist, right? I run my own DNS and didn't find it too tricky, although I have one hostname that won't exist again until sometime next decade because of an extra zero in a TTL number in some file ... fortunately, it wasn't a needed prefix...
That said, what have you found at Google? Try "DNS forums" --- where you could post your questions, got opinions. Try "DNS help" --- but 'caveat emptor'. Try "named tutorial". If you run Unix/Linux, read the manpages for named. ...
HTH,