So to confirm your behavior, you can tailscale ping each other fine and tailscale ping to the internal network. You cannot however ping from the OS to the remote internal network?
Exactly.
Have you checked your routing tables to make sure the tailscale client added the route properly?
How do I do this? I use Headscale and headscale routes list shows the following:
ID | Machine | Prefix | Advertised | Enabled | Primary
1 | server | 0.0.0.0/0 | false | false | -
2 | server | ::/0 | false | false | -
3 | server | 192.168.178.0/24 | true | true | true
Also have you checked your firewall rules? If you’re using ipfw or something, try just turning off iptables briefly and see if that lets you ping through.
I'm not using a firewall, but the VPS is hosted on Hetzner, which has a firewall. But I already allowed UDP port 41641 and 41641. The wg0 rule is from the Wireguard setup I want to replace using Tailscale.
# iptables --list-rules
-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT
-N DOCKER
-N DOCKER-ISOLATION-STAGE-1
-N DOCKER-ISOLATION-STAGE-2
-N DOCKER-USER
-A INPUT -s 100.64.0.0/10 -j ACCEPT
-A FORWARD -j DOCKER-USER
-A FORWARD -j DOCKER-ISOLATION-STAGE-1
-A FORWARD -o docker0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -o docker0 -j DOCKER
-A FORWARD -i docker0 ! -o docker0 -j ACCEPT
-A FORWARD -i docker0 -o docker0 -j ACCEPT
-A FORWARD -i wg0 -j ACCEPT
-A DOCKER -d 172.17.0.3/32 ! -i docker0 -o docker0 -p tcp -m tcp --dport 443 -j ACCEPT
-A DOCKER -d 172.17.0.3/32 ! -i docker0 -o docker0 -p tcp -m tcp --dport 81 -j ACCEPT
-A DOCKER -d 172.17.0.3/32 ! -i docker0 -o docker0 -p tcp -m tcp --dport 80 -j ACCEPT
-A DOCKER -d 172.17.0.5/32 ! -i docker0 -o docker0 -p tcp -m tcp --dport 9090 -j ACCEPT
-A DOCKER -d 172.17.0.5/32 ! -i docker0 -o docker0 -p tcp -m tcp --dport 8080 -j ACCEPT
-A DOCKER -d 172.17.0.6/32 ! -i docker0 -o docker0 -p tcp -m tcp --dport 443 -j ACCEPT
-A DOCKER -d 172.17.0.2/32 ! -i docker0 -o docker0 -p tcp -m tcp --dport 9001 -j ACCEPT
-A DOCKER-ISOLATION-STAGE-1 -i docker0 ! -o docker0 -j DOCKER-ISOLATION-STAGE-2
-A DOCKER-ISOLATION-STAGE-1 -j RETURN
-A DOCKER-ISOLATION-STAGE-2 -o docker0 -j DROP
-A DOCKER-ISOLATION-STAGE-2 -j RETURN
-A DOCKER-USER -j RETURN