You can normally set a range of ports on port forwards. Usually it’s separated by a - was or :

So 30211-30217 or 30211:30217 etc (I don’t know if that’s the range, I’m on mobile now, just an example)

Your router UI should tell you. But if you can’t set a range (I wouldn’t put it past some manufacturers) then yeah, I’d do all of them.

There’s scant documentation on what they do but I have observed them used when messing with the traffic on my network. These connections seem to be built when doing something transactional (buying shit, spending cash/gold etc) but i haven’t looked much deeper into it beyond just monitoring connection states.

fWIW I came to this via testing. My goal was to try and get a way to get into a solo session. In GTA you could do this by killing/dropping the player connections a few times. This is why the hack back in the day was to quickly dicosnnect/reconnect your cable or flip to wifi to get into a solo session in GTA

In RDO doing this too much will also give you this error. So it seems rdo servers have a bit more logic and if they see you dropping player connections (that the server can still see) you get dropped with 06 error. Additionally if you drop the RDO connection it will rebuild once. Then rebuild using their proxy then just drop you. They are trying to keep the session active but they are fighting consumer firewalls that use a lot of smoke and mirror “features” to protect you, and they really aren’t designed to handle incoming traffic or bidirectional traffic beyond TCP acks etc. also home networks are usually not the most stable. It’s why I think rockstars choice in their online design sucks, and sucked with GTA too.