Hi,

I'm looking for some help from the collective with a site to site VPN link.
It's a satellite office link to main HQ and has been running quite happily with 2 RT2600ac routers in site to site mode.
Now the satellite office is being upgraded to a 4G LTE link, so can no longer use site-to-site setup. No problem - fire up the old pfSense box and connect the satellite office as a VPN client. Got this all working, can ping from the satellite office to the main servers, but can't get traffic going back the other way. Feels like I'm missing a route on the Synology, but can't see where to add it... when setting up static routes, there is no option to use the VPN interface as a destination, only LAN, WAN, internet etc.

What am I missing???

Details:
Satellite office uses 192.168.10.0/24 IP range
Main HQ uses 192.168.15.0/24 IP range
OpenVPN tunnel from satellite (pfSense client) to main (Synology RT2600ac server) on 172.22.0.x.
The tunnel is up and running and I can trace the route correctly from the 192.168.10.0 network all the way to an end server on the 192.168.15.0 network.
However, traffic from the 192.168.15.0 network is getting lost - I can ping the tunnel endpoints from the 192.168.15.0 network, but can't find where the route gets setup.

Thanks,

Scott