J PS4 NAT Fix

How to get PS4 to report NAT type 2 when at university?

Problem is that he cannot port-forward the required ports to his PS4. The fix is to route all his PS4 traffic over a VPN to home and port forward from our home ADSL to his PS4.

Multiple steps needed and a few false starts so far.

Update

Update 26th January 2023 - although we have got each bit to work they are not all working together. I think the reason the change in Linux bridge network introduced into the kernel a couple of years ago, called DSA. I need to document how to change the networking, so that the ‘main’ interface is a bridge interface and the other ‘virtual’ interfaces are linked to the bridge (think of a bridge interface as a network switch). I have also been reading up on VLANs; a plan is to try using VLANs to link PS4 LAN to home LAN.

Raspberry PI had no route back to PS4 - fixed by

sudo ip route add 192.168.181.0/24 via 192.168.100.2 dev tun0

But removed some other rules to find that, which break PS4 NAT test.

Overview

Tell PS4 it has IP address which is a subnet of the home network. Link that subnet to home using a VPN tunnel.

Issues are:

• University network does not support UPNP or port forwarding.
• Our ADSL router does not support subnets and additional static routes.
• UDP is needed, so usual solution of port fowarding over SSH tunnels is not suitable.

Target

• PS4 has IP address 192.168.181.4/255.255.255.0 with a gateway of 192.168.181.254 (or perhaps .2)
• Thinker runs OpenVPN with IP address of 192.168.181.2 connecting to pi1 with address of 192.168.181.254
• pi1 runs router with port forwarding to forward

OpenVPN

Thinker and Pi1 have been linked using OpenVPN.

This needs testing, it was tested from Thinker to Far1 - dad has since moved the config files (and port forward from ADSL) to pi1.

IP Addresses

NOTES

• Currently uysing IP address on tunnel of 192.168.100.1/2/254.
• Set
• the home ADSL router considers it part of the address it can manager (192.168.182.254/22 = 192.168.180.0-192.168.183.255)
• dad starts OpenVPN server with the command sudo systemctl start openvpn@juni.
• J need to try command sudo systemctl start openvpn@client
• need to add OpenVPN ccd files so Thinker knows to route 192.168.182.* via pi1 and needs to know to route 192.168.181.* via Thinker.

iptables commands

On Thinker

Route all traffic from PS4 (192.168.181.4) to ADSL router (192.168.182.254)

iptables -t nat -A PREROUTING -s 192.168.181.4 -j DNAT --to-destination 192.168.182.254_

On pi1

Route all traffic incoming on forwarded ports to PS4

 2007  sudo iptables -t nat -A PREROUTING -p tcp -m multiport --dports 3478:3480 -j DNAT --to-destination 192.168.181.4
 2010  sudo iptables -t nat -A PREROUTING -p udp -m multiport --dports 3478:3480 -j DNAT --to-destination 192.168.181.4
 2009  sudo iptables -t nat -A POSTROUTING -j MASQUERADE