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Preparing to establish multisite Exchange servers

Do you have to configure Exchange servers for multiple locations in your organization? Getting them to communicate with each other can be tricky. In this Daily Feature, Ron Nutter shows you how to prepare to make them talk to each other.

In a semiperfect world, you only have to administer one Exchange server. Nevertheless, at some point, you may have to deal with an Exchange configuration that contains more than one server and more than one location. Don’t panic. This isn’t as hard to do as you would think. In this Daily Feature, I’ll show you how to deal with a multisite Exchange configuration.

Getting started
There are a few things you need to put in place before starting the Exchange configuration. Assuming the second location that you want to be in your Exchange system is in a separate domain, you’ll need to have two-way domain trusts in place and use either WINS or LMHOSTS files.

For a multisite configuration to work, you’ll need to either have a direct-data connection between locations or have a VPN in place if you are connecting your sites via the Internet. The method we will be using to connect the Exchange servers together will require either a direct-data connection or a VPN connecting the networks together, as RPC (Remote Procedure Calls) is used by the Exchange server handling the server-to-server connections.

The two Exchange components you will be using are the Site Connector and the Directory Replication connector. The Site Connector is the piece that will get the two Exchange servers talking together. The Directory Replication connector is the part that will replicate the Recipients container between the Exchange servers. Once you have this part up and running, don’t expect instant results. The replication process will take at least 10 minutes and can take upwards of several hours on larger networks.

One important thing to remember is that you’ll need at least a 64-Kbps line in order for multisite Exchange configurations to work seamlessly. The faster the connection, the better it will work.

In the configuration I used in writing this article, I had a full T-1 for one end of the connection going to one ISP and a fractional T-1 (128 K) at the other location going to a different ISP. I used Nortel’s Contivity VPN solution to link the locations together.

Installing Exchange at the second site
Before installing Exchange on the second server, there are a few things you should do to make your life a little easier. At the second site where you are about to install Exchange, create an Exchange service account to handle the startup tasks for Exchange. Put the Exchange service account in the Domain Admins list on the first network where Exchange is already running.

Once you have done this, put the Exchange service account on the first network into the Domain Admin group on the second network. You’ll now repeat the process with a little bit of a twist. Go into Exchange Administrator on the first network, and grant the Exchange service account on the second network Permissions Admin rights. Repeat this process on the second network, but this time use the Exchange service account from the first network.

When you install Exchange at the second site on your network, do everything identical to the way you did it on the original server—up to a point. When the Organization And Site screen appears during installation, click on the Create A New Site button. Enter the Organization name for your existing Exchange installation and enter the site name in which you want this server to appear. In this case, the Exchange server being installed will be in a separate site container, mainly due to the second server being in a physically separate location from the first server in this configuration. Click OK to proceed.
When I install Exchange servers, I almost never take Microsoft’s default selections. For example, when choosing an application directory to which to install Exchange, I try to set up the first drive or volume for NT system use only; the next drive or volume (usually about 4 GB or so) is reserved for sole use of the NT swap file, and the remainder is set up for Exchange executable files and data files.
I also suggest using the Complete Custom option during installation. By default, several additional connectors for services, such as MS Mail, are installed that you probably won’t need and that take additional memory you can use elsewhere. On the next screen, select Microsoft Exchange Server and click Change. Deselect the check box for the items you don’t want to install (such as the connectors that I just mentioned earlier). Unless you are really tight for disk space, I would also suggest installing the online documentation to keep from having to hunt down the CD when you need to reference configuration setup information.
A site service account screen will appear. I suggest that you set up a separate site service account for each additional Exchange server to be set up. Doing so will create a local account each Exchange server can use to start up without having to authenticate across a slow WAN link. It also eliminates the problem of the server not being able to start up in the event that the WAN connection is down. Then, you can continue the installation as you usually would. Just make sure you run the Exchange Optimizer.
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