SharePoint 2013 Apps with Alternate Access Mappings, don’t work with RTM. This facility was added in the March PU. With RTM in fact, you couldn’t even use host-header web application configurations.
It is important to know that the March PU still doesn’t enable this facility by default, you have to actually enable it. Even when you enable it, there are some important restrictions/rules to remember/keep in mind.
You configure the app domains on various zones, using PowerShell. There is no UI to do this. In order to do so, you would use the following PowerShell commandlets,
Also, you have to setup a reverse proxy to allow traffic to the app domain.
When setting up app domains, you need to keep an important restriction in mind. The multiple web applications sharing the same app domain, must all share the same application pool account, and the same authentication scheme.
Another restriction you need to consider, is that you can’t use ports that are already being used when you configure app domains. This is a big issue when setting up app domain to use SSL. If your app domain wishes to use SSL, it must use SSL on a port other than the web application SSL Port. And you should never use apps without SSL, so you can pretty much guess what this means. Yeah I wasn’t too ‘appy about it either.
Before you can configure an App Domain to be used with a web application using the commands above, you need to enable multiple app domains on your farm using the following Powershell script,
1: $cs = [Microsoft.SharePoint.Administration.SPWebService]::ContentService
2: $cs.SupportMultipleAppDomains = $true