I'm a complete noob at running my own server, and I want to install 3 different sites to be served from my Mythbuntu 14.04 system at home. What I want to do is not for actual public access though, but just me and maybe a small circle of other people. However, I want the sites to be publicly reachable in the sense that I can access them from any place outside my home network. However, I don't want to rent a domain for them, but access them just by the IP addresses.
My question is: how about public IP addresses? Do I need to have as many as the number of sites I want to host? I have a normal home DSL internet connection, and I think my ISP may only be handing me a dynamic IP address - but I still have to verify that, it may also be static. In short, is it possible to host like three sites, accessible from outside, on the same box, over this infrastructure, or would I need to make arrangements with my ISP for a different setup?
EDIT: Thanks for your answers, I'm not sure though I got it all figured out:
It seems that If I have a static IP, I don't need the DynDNS service, correct? It seems that I actually might, but I sent e-mail to my ISP to confirm (EDIT: no, it's dynamic).
Checking my router's control panel, I can't find a proper interface for port management. This router actually belongs to the ISP, it's a Technicolor Gateway TG788A1vn.
It has a panel for managing firewall settings with just three preset security levels, and basically that's it for managing the firewall!
In addition, I can "assign" applications,
I suppose the router manages the respective ports, but I'm not sure if "assigning" the https server means it gets to communicate through port 80. Would you think that's what this panel does?
About the domain name vs. IP-only, I'm not actually opposed to using a domain (although IP-only might have a small security benefit?), I just don't want the extra cost. I wasn't aware there are free domains available, so that's good to know! :-)