SNAT over IPSec XGS107-XG135

Hi Dimitris Roubos Thank you for reaching out to the Sophos community team. I would suggest trying with below steps:

On-Site location B, under IPSec site-to-site configuration in Remote subnet details, add the Server IP and vice versa on Site location A under IPSec site-to-site configuration add Server IP in the Local subnet details, with this configuration your tunnel will be up with 2 SA between location B & A and any traffic from site B's local LAN (defined under the tunnel) for Server IP will traverse over IPSec towards site A.

Afterward the above steps, on Site location A please create a VPN to WAN rule to forward traffic over the Server ( Assuming the Server which you want to access is outside on the Internet over the WAN zone, Additionally if on Site location A only 1 WAN ISP is there no SD-WAN rule required but if more then 1 WAN ISP there, please add SD-WAN rule with required source and destination network and select route through gateway with appropriate ISP).

To allow reply traffic of server back to VPN tunnel towards site B add VPN to VPN rule on site A location. Please try this and let us know how it goes..!

Hey Dimitris Roubos ,

Thank you for reaching out to the community, you may refer - Use NAT rules in an existing IPsec tunnel to connect a remote network.

Thanks everyone for your ideas you helped me a lot, but as soon as i realised the concept i understood how to utilize the IPSeC connection.

Network B

I added a static route to the site's IP Address / gateway 172.16.21.254 / interface Network B to Network A

Network A

Then I added 2 firewall rules (1 for each directions) for allowing the site's IP Address is reachable.