Problems hosting simple coop game

[Sir_Lunchalot]

I originally posted this in general discussion, and (quite rightly) it was moved to the multiplayer section. Except that it was put in the Korea multiplayer section, not Great Battles. As a result I am reposting it here:

 

Hello everyone!

 

This is my first post on these new forums. My username was Winkysmith on the old ones, though I haven’t been active for a couple of years at least.

 

So, on to my problem:

I want to host a coop PWCG campaign for myself and a friend, but I am not able to do the necessary port forwarding because my only source of internet is a Telstra mobile hotspot, straight from my phone. I have tried a VPN that supports port forwarding (AirVPN), and acting on the (cautiously followed) advice of Claude AI, have tried to forward the relevant ports that way. Unfortunately, port 28000 was already reserved, but I was told (whether this is correct or not I have no idea) that I could use any port and simply forward it to my pc’s 28000 port.

 

Anyway, none of that seemed to work, so in desperation I have come here in the hope that someone more savvy than me can give me any advice.

 

I have heard about Radmin VPN, but I haven’t been able to find if it works or not, and I haven’t had the opportunity to try it for myself yet.

 

Is there any workaround at all for hosting on hotspot?

 

ANY help would be greatly appreciated!

[jokash]

AI says this 

hort answer: You cannot host a PWCG coop server over a mobile hotspot, even with a VPN.

This is because:

1. Mobile carriers (Telstra included) do not give you a real public IP.

You are behind CGNAT (Carrier‑Grade NAT). This means port forwarding is impossible, even if you “forward” ports inside your router or VPN.

2. AirVPN port forwarding does not work for game servers that require inbound UDP traffic on fixed ports.

IL‑2 uses UDP 28000. AirVPN’s port forwarding is TCP‑only for most servers, and even when UDP is available, the game engine often rejects remapped ports.

3. You cannot “forward any port to 28000” unless the game supports port remapping.

IL‑2 does not. It listens on 28000 UDP only, and clients expect that.

So everything you tried was doomed from the start — not because you did it wrong, but because the network architecture makes it impossible.

[symb]

On 9/13/2026 at 5:36 AM, Sir_Lunchalot said:

 

I originally posted this in general discussion, and (quite rightly) it was moved to the multiplayer section. Except that it was put in the Korea multiplayer section, not Great Battles. As a result I am reposting it here:

 

Hello everyone!

 

This is my first post on these new forums. My username was Winkysmith on the old ones, though I haven’t been active for a couple of years at least.

 

So, on to my problem:

I want to host a coop PWCG campaign for myself and a friend, but I am not able to do the necessary port forwarding because my only source of internet is a Telstra mobile hotspot, straight from my phone. I have tried a VPN that supports port forwarding (AirVPN), and acting on the (cautiously followed) advice of Claude AI, have tried to forward the relevant ports that way. Unfortunately, port 28000 was already reserved, but I was told (whether this is correct or not I have no idea) that I could use any port and simply forward it to my pc’s 28000 port.

 

Anyway, none of that seemed to work, so in desperation I have come here in the hope that someone more savvy than me can give me any advice.

 

I have heard about Radmin VPN, but I haven’t been able to find if it works or not, and I haven’t had the opportunity to try it for myself yet.

 

Is there any workaround at all for hosting on hotspot?

 

ANY help would be greatly appreciated!

I'm not entirely sure whether my tool would help in this particular case, but it might be worth giving it a try.

It was made to work around NAT/CGNAT-related connection problems by redirecting the relevant IL-2 traffic through a virtual LAN such as Radmin/ZeroTier VPN.

More info and the download are here:
https://forum.il2-series.com/topic/5298-il-2-vpn-redirect-%E2%80%94-community-tool-for-natcgnat-co-op-connection-issues/

I may also add support for custom ports to the tool a little later, which could potentially be useful for setups like yours.

Edited September 18 by symb