I have an Exchange 2010 environment in place with Unified Messaging that serves as the voice mail platform for my PBX.  The dial plan is a telephone extension dial plan.  It is configured to use TCP, so no certs or TLS involved.  The UM services are started on the new servers and I moved a test mailbox, but when I try to leave a voice mail it fails and I see the following in the event log:

MSExchange Unified Messaging  - Event 1402

A call for user username@domain.com was received in dial plan CN=Corporate Dial Plan,CN=UM DialPlan Container,CN=corpexch,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=domain,DC=com.  The user is on a legacy mailbox, and the dial plan doesn't have any legacy Unified Messaging servers compatible with the user's mailbox version.  Please verify that your IP gateway or IP PBX is configured correctly.

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I've reviewed this: http://technet.microsoft.com/en-us/library/dn169226(v=exchg.150).aspx

What I haven't done:

1) Move the system mailbox from Step 2, but now I'm afraid.  If I do this, and it's considered legacy like the above moved user because I'm missing something else, do I break production voice mail for everyone on 2010?

2) Attempted to add the new Exchange 2013 servers to the dial plan because per: http://technet.microsoft.com/en-us/library/aa996399(v=exchg.150).aspx "Client Access and Mailbox servers cant be associated with Telephone Extension or E.164 dial plans, but the servers will answer all incoming calls."

3) Pointed my IP gateway at 2013, it still points directs all calls to 2010.  

Thoughts or am I missing something simple?

• Edited by FredFish3421 Thursday, September 11, 2014 3:51 PM typos

If you havent done #3, then you need to. Point the Gateway to 2013 and it will either accept the connection for the 2013 UM enabled Mailboxes or redirect to the 2010 UM servers.

#1 you can do at any time.

#2 is not required for your architecture.

Thanks for replying, Andy!

I know that if I point my gateway at 2013, I should be fine.  You mentioned that in this article: 

http://social.technet.microsoft.com/Forums/sharepoint/en-US/f622ff81-0d97-44d3-9051-f22c381fe188/exchange-2010-and-um-on-exchange-2013?forum=exchangesvrunifiedmessaging

"Once the SIP connection is pointed to 2013, it will handle both the 2013 and 2010 Mailboxes in the Dial Plan" which I found and which was helpful.

But, in the TechNet walkthrough: http://technet.microsoft.com/en-us/library/dn169226(v=exchg.150).aspx 

And the checklist too: http://technet.microsoft.com/en-us/library/dn169228(v=exchg.150).aspx

It's having us move the UM enabled users before we repoint the IP gateway, which is one of the final steps. Since we're just in pilot mode right now, we'd prefer to not re-point that just yet.  Do you expect it shouldn't work?  Is TechNet wrong or am I misreading it or missing something else?

• Edited by FredFish3421 Thursday, September 11, 2014 7:50 PM

Well, I can't speak to those technet articles, but for everything 2013, point your connections to a 2013 server. It knows what to do with it. The same can not be said of 2010 knowing what to do with a client connection destined for a 2013 mailbox. 

If you are concerned about it, test on a weekend /after business hours. Point the IP gateway to the 2013 CAS and leave a VM for a 2013 and 2010 Mailbox. It should work. I have never seen it work the other way ( pointing at the 2010 UM servers).

2013 is fully up to date, I think is at Exchange 2010 SP3 RU2.  Is that OK or does it need to be pushed to a higher roll up?

2013 is fully up to date, I think is at Exchange 2010 SP3 RU2.  Is that OK or does it need to be pushed to a higher roll up?

That should be fine.

Your point in #1 needs to be done. Move the system mailbox to 2013, and configure your Gateway to communicate to 2013, it will then be able to proxy for 2010 users.

With 2010 -> 2013 migrations, you can always move a mailbox back to 2010 if you need to, so fear not. ;)

Luke Edson

You don't need to move the system mailbox before changing the IP gateway however. It can really be done anytime. Many prefer to move it early on however.

It's great to know that I don't need to move the system mailbox, and I'm comfortable that once I point the gateway at 2013, all will work.  However, I don't feel it's the right time to point the gateway and I feel like it should work per TechNet but I'm missing something.  I'm double checking patch levels now.

Should Exchange 2010 UM control the entire conversation and proxy to a 2013 mailbox, or would it send a SIP Redirect to Exchange 2013?

A buddy of mine performing an Exchange 2007->2013 UM migration isn't actually having this difficulty, it just worked there, which has me scratching my head even more.  That's why I'm checking patch levels right now, in case the UM servers aren't running at the version we thought.

• Edited by FredFish3421 Friday, September 12, 2014 3:30 PM

Older will generally not proxy to new, you're just asking for trouble if you try to. Sometimes it works, but functionality is nearly always lost.

To save yourself a lot of headaches, have the new environment proxy to legacy, not the other way around.

Luke Edson

I agree, and it will happen, but I'd like to get a few users living on the 2013 environment first to ensure it's stable enough to point my gateways at.  In the pilot period, reboots may happen or services changed, I want to avoid making any potential changes more complex because it went to production immediately by pointing the IP Gateway at it.  Unless by design any my only option, I have to wait.

As far as UM is concerned, what functionality could be lost?  

It's great to know that I don't need to move the system mailbox, and I'm comfortable that once I point the gateway at 2013, all will work.  However, I don't feel it's the right time to point the gateway and I feel like it should work per TechNet but I'm missing something.  I'm double checking patch levels now.

Should Exchange 2010 UM control the entire conversation and proxy to a 2013 mailbox, or would it send a SIP Redirect to Exchange 2013?

A buddy of mine performing an Exchange 2007->2013 UM migration isn't actually having this difficulty, it just worked there, which has me scratching my head even more.  That's why I'm checking patch levels right now, in case the UM servers aren't running at the version we thought.

UM will redirect the SIP. ( 302) You can bump up the event logging on the 2010 UM server and/or do a wireshark/netmon trace of the SIP traffic to see what is actually going on.

Since you're getting a SIP "redirection" instead of Exchange doing the proxying, you're just redirecting the traffic, so you'll lose the Exchange features, such as AA, 2013 transcription, etc... It sorta works, but not really.

Luke Edson

So, we've tested re-pointing the SBC directly to 2013 UM, which works fine except Automated Attendants.  Calls to AA go to 2010 and we get the same old "The user is on a legacy mailbox, and the dial plan doesn't have any legacy Unified Messaging servers compatible with the user's mailbox version.".  

Do I have to move the system mailbox to fix this?  Or something else?

Yes, that's correct.

With the checklist at: http://technet.microsoft.com/en-us/library/dn169228(v=exchg.150).aspx, it's clear that the System Mailbox has to be migrated to the newer environment first.

Luke Edson

So, we've tested re-pointing the SBC directly to 2013 UM, which works fine except Automated Attendants.  Calls to AA go to 2010 and we get the same old "The user is on a legacy mailbox, and the dial plan doesn't have any legacy Unified Messaging servers compatible with the user's mailbox version.".  

Do I have to move the system mailbox to fix this?  Or something else?

Since you are using an AA, yes. If not, you could leave the System Mailbox on 2010 till then the end or move it anytime. In your case however, you will need to move it. AA's are optional of course  :)

I'll let you know how it goes.