I've been struggling for a while to set up site-to-site connection between my two networks.
Both networks run HAOS with tailscale addon installed. The first network runs on 192.168.0.0/24 and the second one on 192.168.1.0/24 (non-overlapping)
On both networks I set up a static route for the other network to go through the IP of HAOS. So on default gateway 192.168.0.1 I set up a static route that forwards all traffic pointing to 192.168.1.0/24 to go through home assistant running on 192.168.0.10.
When I traceroute, the traffic goes to the HAOS IP as defined in the static routes, but doesn't get forwarded through the tailscale network over the tailscale CGNAT.
On the other hand, when I traceroute from within home assistant (using the Terminal ssh addon), the packets successfully arrive at the remote subnet.
So there must be an issue of home assistant forwarding the packets from devices on the local network through the tailscale tunnel.
I checked out the following docs and as I understand it, everything should be set up correctly, except the sysctl.conf, which I'm unsure whether home assistant changes and even whether it does what I need.
https://tailscale.com/kb/1214/site-to-site
This is my addon config in HA
userspace_networking: false
accept_dns: true
accept_routes: true
advertise_exit_node: true
advertise_connector: true
share_homeassistant: disabled
snat_subnet_routes: false
taildrop: false
stateful_filtering: false
I just hope I didn't just kill two evenings trying to achieve the impossible.