Primary Mail is used to retrieve a user's email address.

Mail Aliases are any aliases set up for a user. To view and select from a list of mail attribute examples, click in the Mail Aliases field and then click Examples.

Primary Group is the token number attributed to a user. If this matches a group's Group Token value, it places this user in that group. This attribute should be considered as an extension to the Other Groups attribute for placing a user in a particular group. Not all LDAP directories offer support for it.

Other Groups is the attribute name that describes the group or groups this user belongs to. For Active Directories this is symmetrical to the Group Parent attribute for the group object class that points from each group to its users. If you omit this attribute, or your directory does not support this feature, the Directory Synchronization Client searches for each user in the entire list of groups.

GUID is a unique identifier assigned to each user in a similar manner to the GUID attribute for groups. If you omit this attribute, you should also omit the group GUID attribute.