Can we have same ports for different SharePoint sites on the same Server. If yes How ?

When hosting multiple web applications,WE have to consider to have a different host header or port. 
The combination host header + port must be unique to ensure a fully functional and reachable system.
Example: intranet.abc.com on port 80 and extranet.abc.com on port 80 are ok. [ In this case we have different host headers ]
Also : intranet.abc.com on port 80 and intranet.abc.com on port 85 are ok. [ In this case we have different ports]