TCP 445 and 139

Hi, I'm using 7.6.0.1.  Can someone tell me why I need TCP ports 139 and 445 open to back up a SQL server?  In the doco it says it's used for remote registry, but not sure what impact this has on the backup.  I have a SQL server behind a firewall.  I have opened up 1556, 13724, 13720 and I can back the server up successfully.  I noticed was that ports 139 and 445 were being blocked by the firewall between the master server and the client.  The only thing I can't do is get the policy to auto detect what type of server the SQL server is when you add it to a policy.  I can edit host details though.

Thanks.