Changed IP address of DNS server and now email not going out.

We changed the IP addresses on our internal DNS servers, updated the IPs on DC and Exchange Servers and now exchange server only allows email to come in but no email going out.
CBBNet AdminAsked:
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Hypercat (Deb)Commented:
On the Exchange servers (Edge and Hub), flush the DNS cache.  To do this, open an administrative command prompt and type the following commands:

ipconfig /flushdns [Enter]
ipconfig /registerdns [Enter]

Restart all of the Exchange services.
CBBNet AdminAuthor Commented:
Let me try and see if that works.
CBBNet AdminAuthor Commented:
Did not work
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Hypercat (Deb)Commented:
What error(s) are you seeing in the outgoing message queue(s) on your server(s)?  Any event log errors?
CBBNet AdminAuthor Commented:
Delivery has failed to these recipients or groups: A problem occurred during the delivery of this message to this email address. Try sending this message again. If problem continues, please contact your helpdesk.

The following organization rejected your message: exchangeservername
Hypercat (Deb)Commented:
If you do an nslookup using a command prompt, do you get name resolution for domains that you're sending to?

Look in Server Configuration/Hub Transport/Properties and make sure the External DNS Lookups is not pointing to a specific IP address for DNS that doesn't exist any more.

Make sure you're not seeing any topology errors in the event logs (look for MSExchangeADAccess messages - they should all be informational).
CBBNet AdminAuthor Commented:
Everything looks fine except for an event log Warning for MSExchangeADAccess Event ID 2937.
CBBNet AdminAuthor Commented:
yes, but message where it says it is being rejected is not the actual Exchange Server but a Linux relay box using Sendmail to send out the mail. Mail goes thru coming in but for some reason when the exchange sends it out its rejected.
Hypercat (Deb)Commented:
Does the Linux box authenticate users in some way?  I'm just wondering if the Exchange server is not sending the right credentials or something on to the Linux box because of a problem with the Routing group connector or MTA.  You could try the update recipient method mentioned in that article and see if it has any effect on the problem.
CBBNet AdminAuthor Commented:
NO the linux box doesn't do any authentication.
What happens when you do a manual smtp session to the linux relay from the exchange server (on the exchange server);

telnet linux.relay 25
helo echangeserver
mail from:
rcpt to:
subject: test

(end the data stream with a dot)

have you changed the DNS on the Linux Relay server?

what happens when you change the DNS settings back?
CBBNet AdminAuthor Commented:
I figured out the problem it was on the Exchange Server in the Hub Transport, Send Connectors, Source Server tab. We had the wrong name of the exchange server.

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CBBNet AdminAuthor Commented:
Figured out the problem and solved the issue.
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