Clarify: You want to show mail address instead of display name in the “To”, “From” and “CC” fields

Explanation: When messages arrive to exchange, server will resolve the mail address to those users who exist in the directory, there isn’t a way to change the behavior which is expected by design

Workaround (For Exchange 2003):

Notes: Not recommend [See KB 828770], it also causes all messages through modified SMTP Virtual Server to show mail address instead of display name

  1. Start Registry Editor [Set on server which your mailbox stays]
  2. Locate or create the following key in the registry
    Notes: You might need to create the ”Parameters” key and the <2> key as well, <2> is the SMTP virtual server number
  3. Add the following registry value: Name: ResolveP2 Type: REG_DWORD Value: 0
  4. Also enable ”allow anonymous senders” on the SMTP Virtual Server
    a.  ESM->AG->Server->ServerName->Protocols->SMTP->SMTPVirtualServerName’s Properties
    b. “Access” tab->”Authentication” button->check “allow anonymous senders”

Notes: For Exchange Server 2007, name resolution is forced for MAPI clients, no way to disable

Here’s a 3rd-party tool which can achieve the function you want: WhichAddress

In a migration environment with exchange 2007 and exchange 2010 we have client (outlook 2007) that hangs 10 seconds when sending a meeting that books a resource mailbox residing on Exchange 2010 mailbox server.

Microsoft say:
In a support case to microsoft they acknowledge this problem as a feature in exchange 2010 when booking resourcemailboxes. They state that this is a fix (code release) for office 365 (clod exchange) where microsoft is not using public folders. This fix is for Outlook 2003 clients when connection to the clod. Outlook 2003 use public folder for accessing free/busy information and when microsoft closed this door in office 365 they had to get a workaround for outlook 2003 users. This fix is intercepting outlook 2003 calls to public folder on a mailbox server and redirecting them to webservices (EWS) on a CAS on behalf off mailuser.

Outlook 2010 is not affected like outlook 2007.

This is not a correct picture yet. A better one is coming soon.
1. Client try to get free/busy information from it’s mailboxserver holding public folder
2. Mailbox server trying to access for free/busy information behalf off mailuser insted of accessing public folder.
4. CAS answering mailboxservers request for information.

So this is a fix for exchange in clod only!? – Yes and No…
It is a fix release for both clod and on premise. So it is affection or local environment to and that is bad!

We noticed the following event id’s being generated on the Mailbox server
Time:     2011-04-01 10:39:52
ID:       4002
Level:    Error
Source: MSExchange Availability
Message:  Process 2796: ProxyWebRequest CrossSite from S-1-1-0 to failed. Caller SIDs: NetworkCredentials. The exception returned is Microsoft.Exchange.InfoWorker.Common.Availability.ProxyWebRequestProcessingException: System.Net.WebException: Unable to connect to the remote server —> System.Net.Sockets.SocketException:
No connection could be made because the target machine actively refused it

Why do we have a problem?
Our Exchange 2010 mailbox servers could not connect to
Well, we can not access Internal URL for EWS from our mailboxservers.
Is this correct? No!
But our network design is not letting us do this right now.
When we worked around this problem we no longer have a problem with outlook 2007. So thats good!
But this proxy fix for outlook 2003 in the clod is still affecting outlook 2007 even thou we no longer see a problem.

Patch from Microsoft
Microsoft is releasing a option in Exchange 2010 SP1 RU4. You will have a way to disable the Availability intercept by using the following registry value.

DWORD: DisableAvailabilityServiceCalls
Value: 1 ( Disable)