here is how i do the http stuff - i first sign up for a free dns redirection from no-ip.com, say
http://xxx.no-ip.com, select it and then install their auto ip update client so that no-ip always has my current WAN ip and anything going to
http://xxx.no-ip.com comes to my machine. then i go to godaddy.com and buy the "real" domain name i want, say
www.xxx.com or whatever. godaddy.com has a forwarding section and in there i tell it to forward
www.xxx.com to
http://xxx.no-ip.com:7255, the last part being the port number since port 80 is blocked. just make sure you LAN machine has a static ip and you forward port 7255 to the correct LAN machine, all done with http.
the problem is that it is not easy to redirect the mail, so no-ip.com has a mail redirector where your mail goes to them, and then gets redirected to whatever port you make your mail server receive mail on. the problem is i think it is ~$40/year so it would probably be cheaper to get in on one of these $25/year website deal, if they have what you need.
i started doing this years ago before they were blocking 80 and 25, so now i have a couple domains pointing to my home that do not get email, they would just be websites and then i have one website that i pay yearly for basically just so i have a email address that is not
bob32432@cox.net or whatever.
no-ip or any of the free dns forwarding providers are great for ftp, non-professional websites that can have a name like
http://bob.sytes.net, or easy to remember game servers and such, but until they unblock 25 it is probably cheaper to go with a "real" webserver...