How to find the user / entity an email address is associated with in Exchange 2003

MS Exchange stores the email addresses for all users and other entities within the Active Directory.

It is very easy to add an email address to a User (Email Addresses tab on the properties page for an Exchange Enabled user) or to a public folder (Exchange System Manager > #Organisation# > Administrative Groups > #Administrative Group# > Folders > Public Folders : Select folder, right click > All Tasks > Mail Enable : Select Folder > Properties > Email Addresses) (O.K. easy when you know where to go).

Multiple email addresses can be added for a user or folder - but its very hard to see which email addresses have been assigned to which entity - especially as there are 2 different management consoles dependant on the type of entity, and secondary email addresses are not easily visible without opening the enity that contains them.

If you attempt to assign an email address which is already assigned to another entity, you get the following error message:

This email address aready exists in this organization.

ID no: XXXXXXX Exchange System Manager

Ok - very useful - tells me what the problem is - but nowhere does it tell me what entity has this email address assigned to it.

Fortunately, the active directory is an LDAP data store - and it is possible to run LDAP queries against it.

We can find what entity has the selected email address assigned to it as follows:

• Open the Acive Directory Users and Computers Management Console
• Right Click on the domain > Select Find
• Select Custom Search in the Find field
• Select the Advanced tab
• To find the entity with the email address spamtrap@danlance.co.uk for example, enter the following in the LDAP query field:
(proxyAddresses=smtp:spamtrap@danlance.co.uk)
• This will list the entity containing the email address entered.
• Wild cards can be entered within the email address (*) to return multiple matches.
• If you want to view all the email addresses within the results list, select View > Choose Columns... and select Proxy Address - doing this in assoication with the query (proxyAddresses=smtp:*@danlance.co.uk) will give you a list of all entities within the organisation that have an email address, together with all the email addresses they have.

I hope this is useful for someone - its really not obvious - and there doesn't seem to be an awful lot of information on how to do this out there...