The Recipient Update Service (RUS) is a very important component in your Exchange installation, it is RUS that is responsible for updating address lists and email addresses in your Active Directory.
Many people ask a simple question, "I just created a new mailbox, but when I look at the users properties in Active Directory Users and Computers, nothing is listed on the Email Address Tab, what did I do wrong?", well the simple answer is nothing, the RUS takes it's time to update all the information in AD, so give it some time and everything will appear.
What we will discuss here is how to ensure that the RUS is running correctly and some issue with using RUS in a multiple domain environment.
By default your organization will have two RUS objects (Figure 1):
a. The "Enterprise Configuration" Recipient Update Service is responsible for the updating of the email addresses for the system objects such as the Message Transfer Agent (MTA) and System Attendant.
b. The "Domain" Recipient Update Service is responsible for the updating of the address information for recipient objects in the domain that it is responsible for, in Figure 1 our domain is NWTRADERS
To adjust the properties for the Recipient Update Service, right click over the service and then select Properties, the properties for the Recipient Update Service will now be displayed (Figure 2).
This is the domain that is serviced by this Recipient Update Service.
This is the Exchange server responsible for the creation and updating of the address list for the domain specified in the Domain field.
Windows 2000 Domain Controller
The Windows 2000 Domain Controller that this Recipient Update Service will connect to when it creates and updates the address list.
How often the Recipient Update Service will run, if you leave it selected to "Always Run" it will update once every minute.
It is possible to force the Recipient Update Service to start processing, you have two options "Update Now" or "Rebuild", and both of these options are available by right-clicking on the Recipient Update Service. The "Update Now" option will update the address list with changes, the "Rebuild" option as its name implies will completely rebuild the address list.
In most cases, having a single Recipient Update Service for each Active Directory domain will be sufficient, but if you have a single AD domain that spans across different physical locations it is recommended that you create a Recipient Update Service in each Active Directory site, and also ensure that you have a Global Catalogue server in each Active Directory site also.
OK, so we now understand what the Recipient Update Service does and how to configure it, lets look at a bit of troubleshooting.
The first step in troubleshooting the Recipient Update Service, like most other services is to check the Event Log, we are looking for the events that originated from the MSExchangeAL service.
The next step in troubleshooting the Recipient Update Service is to use ADSI Edit to check a mailbox that should appear in the Global Address List. We need to check and see if the "showInAddressBook" attribute is populated (Figure 3)
If the "showInAddressBook" attribute is not populated, the Recipient Update Service may not yet have run, in most cases manually forcing the Recipient Update Service to run will resolve the problems.
From time to time organizations have multiple Windows 2000 domains that host user's accounts but may only have one domain that hosts their Exchange 2000 servers. In these scenarios we need to create additional Recipient Update Services, or our Global Address List, will not be populated with the account information from the domains that do not host the Exchange 2000 server.
The diagram below shows the scenario that we will use. We have two domains "nwtraders.msft" and "research.nwtraders.msft", our Exchange server (London) is located in the "nwtraders.msft" domain, but we have users in "research.nwtraders.msft" who have mailboxes on our Exchange 2000 server, so we will need to create a Recipient Update Service to keep our Global Address List in order.
The first task that we must perform is to run the Exchange 2000 setup program with the DomainPrep switch in the "research.nwtraders.msft" domain, the person creating the new Recipient Update Service must also have Full Administrative Access on the Exchange 2000 Organization object.
The next step is to create the new Recipient Update Service on the Exchange 2000 server (London).
1. Open the Exchange System Manager, expand the Recipients container, click on the Recipient Update Services container, you should now be shown the existing Recipient Update Services
2. Right click over Recipient Update Services and then select New > Recipient Update Service from the menu, the "New Object - Recipient Update Service" dialogue box will now be displayed (Figure 4).
3. In the Domain box, we need to select the Windows 2000 domain that contains the user's accounts that this Recipient Update Service will manage, in our case "research.nwtraders.msft", you can use the Browse button to select the domain, then click Next.
4. In the next dialogue box (Figure 5) we will select the Exchange 2000 server that will be responsible for updating the Global Address List for this Recipient Update Service, in our case "London", click Next.
5. You will now be shown a summary of the parameters that you entered (Figure 6), if they all appear to be in order, click Finish to complete the setup of your new Recipient Update Service.
Well that concludes my brief rundown of the Recipient Update Service in Exchange 2000, and hopefully this has given you a better understanding of this important Exchange 2000 service.