avast uses the localhost (127.0.0.1) to scan the emails. The messages are received by your ISP and delivered to avast Mail service at the localhost, scanned, and then sent to your email client. I don’t know how AVG and Norton works. I used both but I only ‘learn’ about antivirus using avast.
You must change OE not Firetrust 
Do nothing… The default port for avast to scan is the 110.