Change only the Public URL of an Alternate Access Mapping via PowerShell

Question

this must be possible via PowerShell as it can be done from Central Administration. I have a task to modify just the public URL of an existing alternate access mapping (AAM).

PS U:\> $aam = Get-SPAlternateURL -WebApplication http://mysite
PS U:\> $aam

IncomingUrl             Zone            PublicUrl
-----------             ----            ---------
http://default.mysite   Default         http://default.mysite
http://mysite           Internet        http://mysite

So with the above AAM, in the Internet zone, I need to change the public URL to say http://othermysite

If I run

PS U:\> Set-SPAlternateURL -Identity http://mysite -Zone Internet -Url http://othermysite

I end up with both the public URL and Internal URL changed

PS U:\> $aam = Get-SPAlternateURL -WebApplication http://othermysite
PS U:\> $aam

IncomingUrl             Zone            PublicUrl
-----------             ----            ---------
http://default.mysite   Default         http://default.mysite
http://othermysite      Internet        http://othermysite

As well, Set-SPAlternateURL does not provide an argument -Internal like the New-SPAlternateURL cmdlet.

If I run

PS U:\> New-SPAlternateURL -WebApplication http://default.mysite -Zone Internet -Url http://mysite -Internal

I get the correct aam, but I have two in the list of Internet zone aam now.

PS U:\> $aam = Get-SPAlternateURL -WebApplication http://default.mysite
PS U:\> $aam

IncomingUrl             Zone            PublicUrl
-----------             ----            ---------
http://default.mysite   Default         http://default.mysite
http://othermysite      Internet        http://othermysite
http://mysite       Internet        http://othermysite

If I try to remove the aam

http://othermysite      Internet        http://othermysite

both aam for the Internet zone are removed.

So how can I get the following accomplished via PowerShell, or is this only possible via the GUI in Central Administration?

IncomingUrl             Zone            PublicUrl
-----------             ----            ---------
http://default.mysite   Default         http://default.mysite
http://mysite       Internet        http://othermysite

Answer 1

You need to do this in three steps as the IncomingURL and PublicURL are equal. Start by removing what you have on the internet zone (1) and build your url-structure starting with the PublicURL (2). When that's done - set a new URL for the IncomingURL (3).

#(1)
Remove-SPAlternateURL -WebApplication http://mysite -Zone "Internet"

#(2)
New-SPAlternateURL http://othermysite -Zone "Internet"

#(3)
New-SPAlternateURL http://mysite -Zone "Internet" -internal

Now you have what you wish for:

IncomingUrl             Zone            PublicUrl
-----------             ----            ---------
http://mysite           Internet        http://othermysite

From this setting, you are able to set the publicURL since it differs from the IncomingURL:

Get-SPAlternateURL “http://othermysite” | Set-SPAlternateURL “http://newothermysite”

And the outcome will be

IncomingUrl             Zone            PublicUrl
-----------             ----            ---------
http://mysite           Internet        http://newothermysite

Reference: Remove-SPAlternateUrl, New-SPAlternateUrl and Managing SharePoint 2013 with PowerShell: Working with Alternate Access Mappings

Answer 2

You accidentally wrote "-Zone Internet" in your command. That should be the problem.

The command you need should be this:

PS U:\> New-SPAlternateURL -Url http://mysite -WebApplication http://default.mysite -Zone Default -Internal

Here is an Link to a googlebook where you can find more information how to create AAM's(Chapter 5.7)