Is it possible to run several sites from one web server with 1 ip?

Question

CentOS

There is 1 webserver. It runs 1 site with a bunch of subdomains. ip is static.
Question: can I post 1 more site on it, despite the fact that I have access to the router and I cannot register a name there?
If I didn't formulate my question correctly, please correct me, as I'm still a novice in this matter.

Answer 1

the router is here to the light bulb, it drives data and does not even suspect that it is serving the site.
1. buy/configure a dns record - so that the name of the new site expands into the existing ip-address.
2. the web server installed at the existing ip address must be configured to issue the contents of the new site upon accessing it (the http request contains the site's domain name on it and separation takes place)
read virtual hosting
the number of sites is limited only by the possibilities server.