I'm unsure I completely understand. A few questions:
Are Portal and Server installed on separate machines?
How many web adaptors are you using, and where are they located? There should be two, one for Portal and one for Server.
Portal is on server01.ina.bisnet.com, correct?
If you're installed on two separate machines, then that puts ArcGIS Server on internal.ina.bisnet.com, is that correct?
The response to the call to the SELF resource would be coming from the Portal.