We have a software that the vendor says does not work well with Symantec 12.1. (works with SEP 11) Said it has to do with the communication between SEPM and Client and port 80. Can we setup a group in the SEPM that would disable using port 80 and allow the others like 443
Upgrading from 11 - 12.1.5
Communication is over 8014 with clients so yea you could. 80 was used in older versions of 11.x with IIS. 12.1 uses 8014 (as well as later versions of 11.x).
See this article for details:
Communication ports used by Symantec Endpoint Protection
If you want to change the port, follow this document
You may want to refer this article as well