Class specifies the DNS record class value, almost always IN for Internet. Priority specifies the priority level of the server. Clients will attempt to contact the server with the lowest priority value. Weight is a load-balancing feature. If multiple servers have the same priority, clients choose SRV records with higher weights.
Port specifies the port number that a particular service listens on.
Netlogon service can accomplish re-registration of all SRV records. You should also familiarize yourself with the different subdomains that are created beneath a domain in a Windows 2000 DNS implementation. Service records and related entries can be verified by using both the DNS MMC snap-in, as well as by querying DNS using nslookup.exe . Aside from the details listed above, it is important to understand how to create an initial DNS zone to support Active Directory. This should be done in advanced of installing Active Directory, in order to ensure that things are configured as you wish them to be.