GAL is very easy to Configure out .. just follow these steps.
###Create Address book for GAL in Private user account eg;gal@yourdomian.com ####
1)Just Create new mail account configure for Global Address book , eg.username=gal
2) Go to its mailing account ->Address Book ->Create New Address book ->Name->MyCompnayGAL
3)Add All Email Address with all details regards to your compnay profile
##Associate GAL to your Domain ###
Login to Admin panel
https://yourdomain:7071
Go to Manage Domians->yourcompany Domian->On Above Menu Select->Configure Gal->
GAL mode:internal
Most resutl returnd by GAL serach :100
GAL sync Accoutn Name (gal@yourdomian.com) -> refer to Account created for Address book
DatasoureName for internal Gal:MyCompnayGAL ->Address book Name you created
internal GAL pooling interval:1 ( minutes) ->Gal Update time
##How to Enable GAL on your domain users accounts Globally through COS ##
Go to Admin GUI panel ->Configureration->Class of Service->Default(or any other Active COS )->Features
->General Feautres
Select->Global Addresss List Access
Select->Autocomplete Form GAL
TAB->Preferaence
Address Book Options->
Select->Enable Automatic Adding of contats
Select->Use the Gal when Autocompleteing Addresss
Contact per page:100
Great now all users have Updated Address book with user Address book in
gal@mydomain.com