Why Outlook 2003 is unable to connect to Exchange 2003?

Posted on 2011-10-13
Last Modified: 2012-05-12
Origin: single network single domain (Windows 2003):
default gateway:
svr-exch:; dns =
workstations use dhcp.
all servers and workstations are in the same network.
No issues noticed.

Changes made:
segment workstations from servers as follow:
servers stay the same
workstations are put in network
use dhcp to dispatch ip (10.0.2.x) and dns (;
workstations are able to ping servers by ip and host name;
There are no dc in 10.0.2.x network.

Issues noticed so far (6 days since change):
A few users are not able to open Outlook properly. When setting up the user's Outlook profile again, Outlook says 'The name could not be matched to a ame in the address list'. When trying to set up another user, Outlook is unable to resolve the mailbox even though the mailbox is there.

Q#1. Is the above issue related to the above network change? If yes, what's the ultimate cause?
Q#2. Any potential issues if there is no domain controller in the new user segment? for example, will computer accounts become out of synch with AD?
Q#3. If there must be a domain controller in the new user segment, is it easy to modify svr-dc-dns2 and put it in the new 10.0.2.x network?
Q#4. Will more uses run into Outlook issues?


Question by:richtree
    LVL 23

    Assisted Solution

    by:Stelian Stan
    Can you ping the mail server from the user workstation?
    Is 10.0.2.x network on a different site? If yes it's recommended to have a DC on that site.

    Author Comment

    Yes, workstations can ping all servers by ip and host names.
    10.0.2.X is physically same site as 10.0.1.x,gigabit link between them.
    Please comment on my questions.
    LVL 14

    Accepted Solution

    I guess you have not configured the subnet in ad sites are services and allocated the subnet to a site. Once you have dine this the clients will be able to discover the correct dcs for them to use.

    Author Comment

    Is DC not required in the new subnet once a new site is added in AD?

    Author Comment

    Is it ok to add the new subnet (10.0.2.x) to the site where the original subnet (10.0.1.x) sits?
    LVL 14

    Assisted Solution

    Yes, because what you are saying is both subnets belong to the site. If the subnet was belonging to a different site, say New York, then you would create a site for New York and assign the subnet to it. In your case, just add the new subnet to "Default-first-Site-Name" (unless you renamed the site)

    Author Closing Comment


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