HTTP has some well-known alternative ports, like 8080, etc.
If I need to deploy any service which is served through secure HTTP, or maybe I need to assign any port to a HTTPS service on my local machine, but I already have another HTTPS service handling the 443 port, is there any convention about which port to use?
Side note: this question was posted for reference means since the answer was already posted to a question, but that question was not asking exactly that - anyway the answer was collecting lots of positive votes.
There is no standard about that, but port 8443 is sometimes known as the http-alt, and it seems the only one being popularly used as alternative HTTPS port.
It may have become popular because of mod_nss (an HTTPD module alternative to mod_ssl) using it on its default configuration.
As already stated, I'd say there's no standard alternative port to use. It's up to you which port to use.
Personally I like to use 443xx with xx being any 2‑digit number, e.g. 44301. According to the Wikipedia list of TCP/UDP port numbers, the ports 44300–44399 are unused. (For multiple HTTP ports I use 80xx in the same way. 8008 and 8080 are officially alternative ports for HTTP.)
Note that I use such alternative ports only for temporary or personal web services. If you want to run multiple web services on the same IP in production, I suggest you to set up a SNI proxy such as sniproxy. (However, if your webservices are all running on the same web server such as Apache, setting up virtual hosts is sufficient.)
来源：https://stackoverflow.com/questions/32478277/is-there-any-standard-alternative-https-port