Exchange 2013 Legacy name space when using 3rd party email filtering

So if I want to keep my same IP address so don't have to change the numerous places we have it set.

Do you see any issues if I change the IP address of the server with the current Exchange2007 to something different and set the new exchange2013 to my preferred IP, before I start the upgrade.  

Thank you!

I think the biggest problem would be DNS propagation. Before you switch the IPs around, drop all the Time To Lives (TTLs) on your external hosting provider to 1 hour. If it was set to 48 hours beforehand you will need 48 hours for that new TTL to propagate. Then once everyone knows about your low TTLs you can quickly change things around. I would do this all after hours though.

We use a 3rd party for filtering and they forward all incoming mail mail to an outside facing address thropugh our firewall.  So the way I understand it the DNS settings will only be internal ones which I can set manually.  The external TTL is set to 15 minutes by our provider.

Is there anything that I have wrong or need to consider?  Yes I am doing this after hours.

I think that's it. Going back to my original comment you just need to change the IP of where the 3rd party service routes mail.

I just finished the install and received this error when I opened the Exchange Man Shell:

This is part of the output from the shell, I have attached a file with the complete output.  It looks like it tried 3 times .

The name of the Exchange2007 server is hermes2, the 2013 is hermes3.
The name of our AD is "forsyth"

Any ideas?
Thank you!
------------------------------------------------------------------------------------------
VERBOSE: Connecting to hermes3.forsythpl.org.
New-PSSession : [hermes3.forsythpl.org] Processing data from remote server hermes3.forsythpl.org failed with the
following error message: [ClientAccessServer=HERMES3,BackEndServer=hermes3.forsythpl.org,RequestId=2d2dcfef-3753-4c3e-b
207-3845ca5d6833,TimeStamp=2/23/2015 2:31:07 AM]
[AuthZRequestId=45093630-4a0f-4c08-a5ff-4d6bf230c5b5][FailureCategory=AuthZ-SetupVersionInformationCorruptException]
Unable to determine the installed file version from the registry key
'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell\1\PowerShellEngine'. For more information, see the
about_Remote_Troubleshooting Help topic.
At line:1 char:1
+ New-PSSession -ConnectionURI "$connectionUri" -ConfigurationName Microsoft.Excha ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : OpenError: (System.Manageme....RemoteRunspace:RemoteRunspace) [New-PSSession], PSRemotin
   gTransportException
    + FullyQualifiedErrorId : IncorrectProtocolVersion,PSSessionOpenFailed
WARNING: No Exchange servers are available in the Active Directory site HP. Connecting to an Exchange server in another
 Active Directory site.

Failed to connect to an Exchange server in the current site.
Enter the server FQDN where you want to connect.:
ExchangeManagementShell-Error.docx

Here is what I see in the Event Log on the new Exchange2013 server I see numerous events that have the following in common:

Microsoft.Exchange.Diagnostics.SetupVersionInformationCorruptException: Unable to determine the installed file version from the registry key 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell\1\PowerShellEngine'.


When I look at the registry "PowerShellEngine'" does not exist under PowerShell\1\ but I do see it under PowerShell\3\

Also I am concerned about this error in the Exchange Man Shell:
WARNING: No Exchange servers are available in the Active Directory site HP. Connecting to an Exchange server in another
  Active Directory site.

Our site is "forsyth"  not "HP".  We used to have 2 sites one was HP but HP is no longer in use.

Does HP still exist in Active Directory Sites and Services? If so, and its no longer in use, I would look into removing it. It could also be possible that a subnet that is actually in FORSYTH is assigned to the HP site.

Because these are new questions can you close this one and open a new one? Feel free to reference back to this question as well in your new question.

I had some AD issues which are now fixed

Thank you, I hope to finish up this Sunday