You host netgames, or join the ones already up.
Plus, you can search for netgames, goto "join game (search)" and set it to Internet. if, by any chance, you want to try joining the netgame by IP, then goto "Join (IP address)" and type in their IP address there to join their netgame. If there arnt any, then that just means there arnt any up as of now.
You can also type 'CONENCT
ip address' into the console to join somebody elses netgame.
To find out the IP address, goto
http://srb2.servegame.org/srb2ms_status.php , or type
listserv into the SRB2 console, or go on IRC and connect to irc.esper.net, and write "!gamelist" in either #srb2fun or #srb2general. If you want to host a netgame, head into SRB2, and goto Options, and server options (i believe) and set the "Internet Server" to yes. Next step, get out of the options, and head on over to "host server". If you would like to have random people join your netgame, turn "Advertize my server" on. When you set that to On, occasionaly, if somebody types !gamelist on IRC, this will be displayed:
<SRB2MS> Running SRB2 Netgames ([url]http://srb2.servegame.org[/url])
<SRB2MS> IP: IP ADDRESS | Port: 5029 | Name: NAME OF SERVER | Version: 1.09.2
Then, just change the settings to your discretion and start it up!...But, there is a catch sometimes. For reasons dealing with Ports and Firewalls, some people cannot host. If you want to try dealing with port forwarding to be able to host, i think
www.portforward.com would help you there.
Depending on your internet connection, the netgame might not be as fast as you would like it. There could be control lag, also known as C-lag, which causes your controls to delay, or even some spike lag, where the lag just slows down the game for a couple of seconds, and then starts back up. On the subject of internet connection, if you are trying to host on 56k, dont expect it to run super-fast with 10 people. Ususally, dial-uppers can host 2 fine, DSL can do 8, and T3 and Up can host around 10-13 without much lag.
Enjoy!