Testing LDAP connectivity
From Tech-Wiki
Get the Active Directory Controller:
dig _ldap._tcp.domain.com SRV
Test authentication:
adtest -t auth - r domain.com -u user -w password
Get group membership:
ldapsearch -x -D "User Name" -w user -h dc.domain.com -b "cn=User Name",cn=users,dc=domain,dc=com memberOf