How to forward specific http requests on a specific port from router?

Question

I use a router which distributes internet to 3 PCs through NAT. I have forwarded port 8008 of my router to my PCs port 3127. When I host my site on port 3127, it is visible at

example.com:8008

. However, even though it is default port of http, I cannot see my site on default domain i.e. http://example.com

I use a dlink router.

I want to add a script in my router similar to below, how to do it?

if (http_packet.host == "*example.com*"):   #contains example.com
    forward(port8008)

Answer 1

However, even though [8008] is default port of http, I cannot see my site on default domain i.e. http://example.com.

Port 80 (HTTP) and port 443 (HTTPS) are the only standard ports for HTTP/HTTPS.

If 8008 is an http port, why isn't my site visible?

As mentioned, 8008 isn't an official HTTP port. Typing http://example.com in a browser is no different than typing http://example.com:80. Other ports such as 81, 8008 and 8080 are often used simply because they are visually similar to 80 and aren't in use themselves (in most cases).

If I forward port 80, I fear other computers will not be able to access http sites.

Most communications on port 80 should not be blocked if a request for an HTTP site originates in your network (ex. from a browser on a local machine), even if you are forwarding port 80.

Requests originating outside your network (i.e. someone trying to contact your website) will be forwarded to whatever host you forward port 80 to, but this host can then potentially redirect requests to other hosts or ports (if needed).

if (http_packet.host == "*example.com*"): #contains example.com
    forward(port8008)

This type of redirection can be done but generally is done through a reverse proxy (the host receiving the request, above).