Exchange 2010 internal relay doesn't deliver email to local accounts

Our company has an Exchange 2010 server pulling email from a POP server that is internet facing.  We have users on the POP server as well as on the Exchange server that all share the same domain name.  Sending email from either server is no problem, but I can't get Exchange to send to users on the POP server.  It always comes back as user unknown, most likely because those users indeed are not on the Exchange server.

Is there a way to get Exchange to send to the users on the POP even though they're on the same domain?  I added an SMTP connector that delivers to the POP.  I tried setting the accepted domain to 'Internal Relay' but which worked, but then we couldn't deliver locally.

This setup used to work when we had Exchange 2003.
Who is Participating?
I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

AkhaterSolutions ArchitectCommented:
what you did is correct, you should set the common domain as "internal relay" instead of "authoritative" nothing else to do

what NDR did you get with that config?
lilgoombaAuthor Commented:
There is no NDR, the email just seems to sit in the queue.  As soon as I switch it back to Authoritative, the mail gets delivered.  It seems like it wants to send everything meant for our domain out to the POP server.
AkhaterSolutions ArchitectCommented:
did u restart your smtp service after setting it to internal relay ?
Determine the Perfect Price for Your IT Services

Do you wonder if your IT business is truly profitable or if you should raise your prices? Learn how to calculate your overhead burden with our free interactive tool and use it to determine the right price for your IT services. Download your free eBook now!

lilgoombaAuthor Commented:
I just restarted the transport service, and still nothing.  Set as internal relay, it delivers everywhere EXCEPT locally.
AkhaterSolutions ArchitectCommented:
the one that are supposed to be local are sitting in which queue ?
lilgoombaAuthor Commented:
It's sitting on the Exchange 2010 server.

Another piece to the puzzle is that our 2003 server is still hooked up with most of the mailboxes on that machine.  Could this be causing some of the problems?

When I look at the stuck emails in que, it says that there is a local loop.  What does that mean?
AkhaterSolutions ArchitectCommented:
yea it could be

give me more details about ur email routing
lilgoombaAuthor Commented:
The Exchange 2003 had the SMTP connector that went to the POP server, but it's been removed.  Both servers have a connector that links them to each other which was automatically created during the 2010 install.  Both Exchange servers also have outgoing SMTP connectors for direct internet bound traffic.

The 2003 server has the actual POP connector that pulls the mail to the local accounts.  That's the only reason it's still around.  If mail comes into the 2003 server, it either stores them locally or forwards them to the 2010 server.

I'm just not sure why, when I enable relaying, the local mail goes in a loop.
AkhaterSolutions ArchitectCommented:
the first thing to do is to remove the SMTP connector (sending) from the 2003 and let the Send Connector of 2010 handle all the outbound traffic
lilgoombaAuthor Commented:
Actually, I'm sorry, it's not a connector on the 2003, it's using "Default SMTP Virtual Server".  I can't remove it, but I can stop it.  Will that tell Exchange to send all mail to the 2010 server to go out?
AkhaterSolutions ArchitectCommented:
no don't stop it.

so on exchange 2003 you only have the default smtp virtual server? by any chance is this guy configured with a smart host ?
lilgoombaAuthor Commented:
No, there's no smart host listed under Delivery -> Advanced.

Unfortunately I wasn't involved with the original setup, so I'm sure there are settings here and there that I haven't discovered yet.
lilgoombaAuthor Commented:
More info:  under the Mail tab, it has "Forward all mail with unresolved recipients to host" and then it has the POP server listed.
AkhaterSolutions ArchitectCommented:
alright the queue they are stuck into are they on the 2003 or 2010 server?

is your internal AD name the same as your SMTP domain ?

lilgoombaAuthor Commented:
The queue is on the 2010 server (which is where most of the mailboxes aren't, as I'm discovering).  Our AD name is the same as the SMTP domain.
AkhaterSolutions ArchitectCommented:
"More info:  under the Mail tab, it has "Forward all mail with unresolved recipients to host" and then it has the POP server listed." can you remove this please restart the smtp and try again
lilgoombaAuthor Commented:
Done.  It seemed to work for one email, then it stopped delivering locally.

Although, now I noticed that while in relay mode, mail gets sent to 2010 recipients, only not to the 2003 recipients.  They seem to get stuck on the 2010 server and go in a loop.
AkhaterSolutions ArchitectCommented:
can you confirm this finding ? can u make a series of test to confirm that users on 2010 can indeed receive emails ?

lilgoombaAuthor Commented:
Confirmed.  When it's set to relay, everything works except mail doesn't make it to the old 2003 server.
AkhaterSolutions ArchitectCommented:
well it is kind of logic

once you set it to internal relay (for a reason I can't find now) the 2003 is sending everything to 2010.

2010 is discovering that that mailbox is on the 2003 and will try to send it back and that's the loop...

The question is why 2003 is sending everything to 2010?

My best guess is the difference between the mail recipient policies in 2003 and the accepted domains in 2007/2010.

your best bet is to move all your mailboxes to 2010

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
lilgoombaAuthor Commented:
That's what I was afraid of...I'm doing that this weekend.  I was just hoping to have this work in the meantime.  

Thanks for all of your help, I really appreciate it.
AkhaterSolutions ArchitectCommented:
let's try one more thing please

how many recipient policies do you have ?
lilgoombaAuthor Commented:
This was most likely a problem with having both Exchange 2003 and 2010 in the same organization.  Once we moved everyone to 2010, the problem went away and we're now able to send to the POP server.

Apparently the 2003 <-> 2010 connector will cause a loop in this situation, sending local emails between the two servers until they time out.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.