Can anyone shed light on how I'm supposed to structure an LDAP search filter? I am trying to get a spam appliance to verify users against LDAP.

I can browse and see the directory just fine from the spam appliance, so I have the BASEDN and BINDDN working.

Now I can't figure out the query filter.

When I tell the spam appliance to look for an email address, it comes back with "unable to find USER DN that matched that email address."

Schema: User Defined
Base DN: ou=people,dc=domain,dc=com
Bind DN: uid=zimbra,cn=admins,cn=zimbra

filter = (&(objectClass=*)(zimbraMailDeliveryAddress=$m))

$m is the variable the spam appliance uses to equal the email address.