e-mail address is incorrect

[TekSolutions]

Any time I attempt to send an email to any email address, outside my domain I get the following error message in a return email with the subject Undeliverable: + Original subject

anyemail@anydomain
The domain name in the e-mail address is incorrect. Check the address.


Diagnostic information for administrators:

Generating server: MyMailServer

anyemail@anydomain
#554 5.4.4 SMTPSEND.DNS.NonExistentDomain; nonexistent domain ##

I have deleted the SMTP connector and created a new one.
I have run a nslookup sometimes with success sometimes with failures.
I can ping both primary and secondary domain controllers as well as the mail server on the local network by computer name.
I have cleared the DNS cache on all three servers.
I have rebooted all three servers.

What else can I try?

Everything was working just fine up to yesterday. At some point the power went off on Saturday night. Not sure if this has anything to do with it as I do have a UPS on the servers.

Internet works fine. Email addresses that do not go through exchange also work fine.

All servers are 2008 and Exchange is 2010

Anybody have any suggestions

 

[TekSolutions]

So it appears I have resolved the issue.

It looks as if OpenDNS is for whatever reason blocking email from exchange.

Whether using the external DNS in my DNS settings or in Exchange external DNS using Open DNS mail delivery fails. Using Google DNS mail delivery is successful.

If anybody can weigh in on this issue, any information would be appreciated

 

[58sniper]

Not sure I understand your last reply.

Exchange servers should always be configured with internal DNS servers configured in its NIC settings.

DNS servers should always be configured with forwarders so that they don't use the root servers.

If you have your send connector set to use DNS delivery, and that doesn't work, try telnetting from your Exchange server to a destination system over 25 and see if the connection is established and you can actually send a message in that telnet session.

Do you have your Tek-Tips.com Swag? I've got mine!

Stop by the new Tek-Tips group at LinkedIn.

 

[TekSolutions]

Exchange servers should always be configured with internal DNS servers configured in its NIC settings.

I have done that. I always do with statics

DNS servers should always be configured with forwarders so that they don't use the root servers.

I have done that as well. DNS forwarders are configured with OpenDNS DNS numbers

What I did to be able to send mail was in EMC I went to Server Configuration --> Hub Transport, right clicked on my Exchange Server and selected Properties, then in External DNS Lookups I entered Googles DNS numbers.

Then In the Send Connector properties on the Network tap selected Use External DNS Lookup settings on the transport server check box