How to connect to a specific Global catalog (GC) with Exchange 2003
John has been doing a series of blogcasts showing how to create a secure, well managed infrastructure, and he's up to the stage where Exchange is fully installed and functional. He's been getting several mails asking him questions about Exchange which he passes over to me. Here's an example of a recent query
We have an exchange 2003 infrastructure running in a windows 2003 server AD environment across. We have 6 campuses, each with their own GC/DC and Exchange server. The problem we are experiencing is that all of the exchange servers are only seeing one of the GCs... i.e. Exch Server on Campus 3 will hop across the wan link to access the GC on Campus 1 instead of using it's own GC on campus 3.
Well, you can force an Exchange client to connect to the nearest Global Catalog Server, or you can set your preferred GC in the Registry. Here are the 2 ways you can go about this...
How to set the closest global catalog server
Use the following steps to force Outlook to identify and use the closest global catalog server.
1. Click Start, and then click Run.
2. In the Open box, type regedit.exe, and then click OK.
3. Locate and then click the following key in the registry:
HKEY_CURRENT_USER\Software\Microsoft\Exchange\Exchange Provider
Note You may have to create the registry path.
4. On the Edit menu, click Add Value, and then add the following registry value:
Value name: Closest GC
Data type: REG_DWORD
Radix: Hexadecimal
Value data: 0x00000001
5. Quit Registry Editor.
How to set a specific global catalog server
To force Outlook to use a pre-defined global catalog server, use the following steps to set the following special registry parameter to point to the Fully Qualified Domain Name (FQDN). Doing this overrides any setting in the MAPI profile.
1. Click Start, and then click Run.
2. In the Open box, type regedit.exe, and then click OK.
3. Locate and then click the following key in the registry:
HKEY_CURRENT_USER\Software\Microsoft\Exchange\Exchange Provider
Note You may have to create the registry path.
4. On the Edit menu, click Add Value, and then add the following registry value:
Value name: DS Server
Data type: REG_SZ (string)
Value data: FQDN of the global catalog server
You can find out all about how the GC works here and there is a description about how you can customise which GC Outlook connects to in the KB here...
And don't forget the 4:1 rule if you're planning your Exchange infrastrucuture. 4 Exchange processors to 1 GC processor. THen you'll get optimum GC performance...