I tried to telnet to mhd01 the Windows DC and it's fine I do get a connection for both computername and FQDN. On mt_srv which is the Linux with Samba box I get "connect failed" as I don't use LDAP with Samba so no LDAP service running, do I need LDAP account management in Samba for active scanning to work? But mt_srv and the Samba domain is not that important as LS works fine via the login script. The critical part is mhd01 and the CORP domain which is an AD domain.
For workgroup, I added the alternative credentials with workgroup and .\username. Now what do i put in the active scanning section, Domain DNS Name = workgroup and Domain Netbiosname = computername?