Description:

nslint is a lint-like program that checks DNS files for errors. DNS or
Domain Name System generally maps names to IP addresses and e-mail
addresses in a hierarchical fashion.

Errors detected include missing trailing dots, illegal characters (RFC
1034), A records without matching PTR records and vice-versa,
duplicate names in a subnet, duplicate names for an address, names
with CNAME records (RFC 1033) missing quotes, and unknown keywords.