Do you want to be sure with DC SRV record registration in DNS?
Run NSLOOKUP command, change type to SRV (set querytype=srv) and then run query for particular domain using _LDAP. For example:
_ldap._tcp.dc._msdcs.domain.suffix or _ldap._tcp.dc._msdcs.subdomain.domain.suffix.
Never underestimate that! Properly configured DNS server is the basic stuff for many other services!