Anonymous logins windows 2000 server

I have a windows 2000 server used mainly for file sharing and backups.
It runs as part of a domain.

All shares are locked to either the administrator and a group of users
who are authenticated through their domain account.

I have also set the local policies - security options - do not allow
enumeration of SAM accounts and shares.

Using a program called dumpsec I can do a dump of all the shares and
see the owners and permissions which is a major concern.

In event viewer, security I have numerous successful anonymous logins,
is there anything further I can do to lock these out.

Thanks in advanc
Cath