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Exchange 2010 GAL Segregation / Segmentation

Basically, this will separate the global address lists (GALs) in exchange 2010 SP2 so you can host multiple organizations and they won’t pick up each other.

You must have Exchange 2010 SP2 or better, and it cannot be a domain controller (DC).

GAL Segregation

Each company will need all of these steps applied with different names for the custom attribute and various lists. Exchange cannot also be a domain controller or it will still load all users in address book.

1. Create an organization unit for the group

2. Set a custom attribute for the OU to share between all users and lists, exchange shell


Get-Mailbox -OrganizationalUnit “path to user folder” | Set-Mailbox -CustomAttribute15 “somename”

3. Create a GAL with the custom attribute in exchange shell

New-GlobalAddressList -name “company name” -RecipientFilter {(CustomAttribute15 -eq “somename”)}

4. Open EMC and go into organization config, mailbox, address lists. Create a new address list using the OU created earlier. Set the custom attribute to what you specified.

5. GO to Offline Address Book tab and create a new OAB using the address list just created.

6. Go to Address Book Policies tab and create a new policy based on the new GAL, OAB, and Room list (address list you made). Add the address list of the addresslist you made again.

7. Apply the new address policy using exchange shell.

Get-Mailbox| where {$_.CustomAttribute15 -eq “somename”}| Set-Mailbox -AddressBookPolicy “Policy Name”