Well there's not a must.You're not much of forwarding ports than making them public. Term of forwarding just came from portforward.comAnyways, some of hosts (your internet hosts) provide public port, where people can connectPorting is needed for people to connect on itIf you host (most common for wifi-es) are private, you need to create a public port where people can connect to otherwise only you and people from same ip range would be able to connect to your server.So you can try inviting people to your server, if they're not able to connect you should make your port public.