Slow delivery between internal users

Posted on 2007-11-26
Last Modified: 2013-11-30
Users are experiencing delays of up to 2 minutes in receiving internal mail.

I have recently started work at this current job andI have inherited the current setup which is Win 2003 domain with Exchange 2003 Ent running on a DC.  I am slowly working to move Exchange to a member server.  Previously the company ran on SBS 2003, which was upgraded to Windows 2003 and Exchange 2003, rather badly.

In the SMTP virtual server settings there are external DNS servers specified, however there are internal DNS servers specified on the network card and internal DNS is configured with forwarders out to our ISP's DNS servers.  Which wins?  and could this be causing the slow delivery?  All the Exchange settings appear to have been copied from the SBS server.

Thanks in advance
Question by:gleads
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LVL 104

Expert Comment

ID: 20351045
Those DNS Servers on the SMTP virtual server should be removed, although they will have no effect on internal delivery.
Do you have message tracking enabled? That will show if there is a delay taking place.
Are you using cached mode? Sometimes a delay can be seen using that, but there isn't a delay in the delivery, but a delay in Outlook updating.


Author Comment

ID: 20351104
Hi Simon, thanks for the quick response.

I would assume that as cached mode is setup by defualt when creating a mail account in outlook 2003 that it will be.  The message tracking shows that the message is delivered in the same minute it was sent, so your theory sounds about right.

Is there anyway to correct this without removing cached mode?

With regards to removing the external DNS entries can this be done without rebooting or restarting services? and will it automatically fall back to the DNS servers specified in the NIC settings?

LVL 104

Accepted Solution

Sembee earned 250 total points
ID: 20351150
Exchange by default will use the DNS Servers listed on the NIC, so remove the DNS Servers. The most you may want to do is restart the SMTP Server Service.

Cached mode updating delays are usually caused by firewalls. If you have the Windows Firewall enabled then ensure that Outlook is on the exception list.

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Author Comment

ID: 20351263
Hi Simon

The firewall is disabled by group policy.  I have seen a similar issue before where if ICMP packets are not specified as allowed on NIC's even with the firewall turned off users have to click out of a folder before it updates and notifies of new email, however this is not the issue here.

Given that the message control centre is showing the message as delivered within seconds of being sent I am inclined to think this issue does not reside with Exchange but more likely with the client.

With the external DNS will it be using the NIC settings now or using the external settings? 2 of the DNS servers in the list appear to be switched off and the third seems to randomly respond, which would explain why I am seeing mail queueing in the connector queue.  If not then that is a separate issue.

LVL 104

Expert Comment

ID: 20354274
If you remove the DNS servers from the SMTP virtual server then it will use whatever DNS is on the NIC. The NIC should be pointing at the AD for DNS only. What you do on the DNS Server applet is down to you. You can either use root hints or your ISPs DNS servers.


Author Comment

ID: 20356276
Thanks for your help.

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