Google Apps Directory Sync Administration Guide - Manual (Page 54)

54 Release 4.0.2
Google Apps Connection Settings
Enter your Google Apps connection information in this section.
Specify the following:
Google Apps Setting Description
Primary Domain
Name The primary domain you want to synchronize. You
must use your primary domain in Google Apps, not a
domain alias.
If you enter a domain that is different from the domain
on your LDAP server and select the Replace domain
names in LDAP email addresses, Google Apps
Directory Sync renames all users and use the Domain
name listed here instead.
Example: example.com