I found the article I was mentioning earlier.
https://enterprise.arcgis.com/en/portal/latest/install/windows/determine-your-organization-s-url.htm
I play it safe and interpret statements like:
- Before installing ArcGIS Enterprise, identify the URL that will be used to represent your ArcGIS Enterprise organization
- The configuration described in this topic must be performed before federating any ArcGIS Server site with your ArcGIS Enterprise organization
- Adding a DNS alias or reverse proxy after an ArcGIS Server site has been federated with your portal is not supported
as meaning that we should choose a DNS/URL before we install; deploy/configure to it, and then stick with it.
However, I do note that at 11.1 Esri state:
"If you need to change the hostname in your organization URL, contact Esri Professional Services or another trusted consulting partner for guidance."
I'd like to think of myself as a trusted consulting partner, but frankly I wouldn't want to take this task on. 🙂
As mentioned elsewhere, I'd be requesting retention of the original URL to save a world of pain.
Scott Tansley
https://www.linkedin.com/in/scotttansley/