My friend and I want to play local co-op games remotely through Parsec. It worked normally while he was living in Hungary, but since moving to Germany and switching to Vodafone internet through a SIM card in his router, Parsec fails with error 6023. We have tried disabling the Windows Firewall and enabling UPnP on the router. Could the issue be that his connection is behind CGNAT and needs a public IPv4 address, or is there another setting we should check?
3 Answers
This is probably a connectivity problem caused by CGNAT. Mobile and SIM-based internet commonly puts customers behind a shared public IP, so incoming peer-to-peer connections and port forwarding won’t work. Ask Vodafone whether they can provide a real public IPv4 address. Another option is a VPN that supports port forwarding, such as AirVPN or Proton VPN, although a regular VPN like NordVPN usually won’t solve this.
I wouldn’t leave the Windows Firewall disabled as a troubleshooting solution. Turn it back on and create an exception for Parsec instead. Also check whether the router actually supports UPnP over the mobile connection, since enabling the setting won’t help if the provider’s network blocks incoming connections.
Parsec depends on peer-to-peer connectivity, and it can become slow or fail completely when neither side can receive forwarded connections. If getting a public IP isn’t possible, try a virtual LAN tool such as Hamachi or another game-networking alternative. It may work even when the router connection is behind CGNAT.
That makes sense. We’ll check whether Vodafone can provide a public IPv4 address first, then try a virtual LAN option if they can’t.