Hi!

We have Exchange Server 2007 and I want to deploy Exchange 2013 paralell as test platform at first, and then in a couple of months migrate.

Exchange 2013 will be accessible only from internal network, There will be one mailbox, moved from Exchange 2007.

1. Will this mailbox fully functional?

2. Can I access this mailbox through CAS 2007?

3. Are there any other problems, that I can have in this configuration?

Thanks in advance.

Hi!

We have Exchange Server 2007 and I want to deploy Exchange 2013 paralell as test platform at first, and then in a couple of months migrate.

Exchange 2013 will be accessible only from internal network, There will be one mailbox, moved from Exchange 2007.

1. Will this mailbox fully functional?

2. Can I access this mailbox through CAS 2007?

3. Are there any other problems, that I can have in this configuration?

Thanks in advance.

First thing I would say is to look at these links:

http://blogs.technet.com/b/meamcs/archive/2013/07/25/part-1-step-by-step-exchange-2007-to-2013-migration.aspx

And the Exchange Deployment Assistant:

https://technet.microsoft.com/en-us/exdeploy2013/Checklist?state=2419-W-AAAEAAAAQACIAAEAAQAAAAA~

You can make it so Exchange 2013 is not accessible from the internet (but if you want to test functionality to make sure it works I would have both 2007 and 2013 accessible from the internet)

Answers to your questions:

1. Assuming you follow the steps above to establish coexistence everything should function.  
2. No, Exchange 2007 cannot access an up revision mailbox via OutlookAnywhere, Autodiscover, or OWA.
3. Make sure you follow the steps in both the guides above.

and nothing will break unless you change the DNS settings. To do a complete pilot test you must allow to test externally including email flow. You will need to install SSL for OWA and ActiveSync to work. If you have wilkd card cert you are good and if not it sill works but not a 100% test.

hope that helps

Agreed with above mentioned suggestions.

Without making any changes with DNS setting, it should not be affecting any of the pattern.

Moreover, while need to migrate users mailboxes from Exchange 2007 to 2013, you may also consider on this automated solution(http://www.exchangemailboxmigration.com/) that could be a nice alternative approach for successful migration of users mailboxes without downtime.

No, Exchange 2007 cannot access an up revision mailbox via OutlookAnywhere, Autodiscover, or OWA.

Hinte- this is what I said twice in the plain english - you don't need to repea