Online play is supported via a direct connection system. Either connect to existing public servers, add a private server, or host your own.
The Server Browser
The server browser lists available servers and their status (such as if a password is set, or if there's room for a player to join). There are many official servers that are automatically shown in the list, and any servers you join via IP address will be saved here automatically.
Only official servers and ones that you have added will be shown, it won’t search for every single server that is running on the Internet.
Adding/Joining Other Servers
To join a server and add it to your server list, press Orange in the server browser. You will need to obtain the IP address and port of the server you are wanting to connect to, along with the password if one is set. You don’t need to open any ports to join a server, but you will still need to ensure that your firewall is not blocking inbound/outbound data to the game.
Hosting a Server
You can host a server either from inside the game, or by using the separately-downloaded standalone server. The standalone server is meant for running a server without having to run CH itself, which means you can run it on other devices and have it be operational 24/7, if you so desire.
When hosting, you will need to make sure that your firewall doesn’t block CH or the standalone server from sending or receiving outbound or inbound data, or that it is disabled while you are hosting (not recommended).
You must also make sure you have the port you are hosting on a port you have forwarded in your router. The default port is 14242, but it can be changed when hosting. Only the host needs to have their port opened.
The easiest way to ensure your port is opened is by enabling UPnP (Universal Plug ‘n Play) on your router if it allows it (some routers/ISPs don't allow UPnP), which will automatically open the port for you when you host.
If you can't use UPnP, you must forward the port manually in your router settings. Each router is very different when it comes to their settings pages, a quick online search for your make/model of router will get you where you need to go.