IPSec VPN TELTONIKA RUT240 and SOPHOS XGS

Question

Hello everyone, 
 I have successfully established an IPSec site-to-site connection between a SOPHOS XGS firewall and a RUT240 from Teltonika. 
 A ping from the Teltonika router to the SOPHOS firewall works. A ping to an end device behind the SOPHOS firewall also works. 
 A ping from the SOPHOS directly to the Teltonika router works. However, I cannot reach any end device behind the Teltonika router. 
 If I do a route tracing on the SOPHOS, it looks as if the route only goes as far as the Teltonika router and then either no further. 
 Where is the error?

emmosophos · Accepted Answer

Hello there, 
 Thank you for contacting the Sophos Community. 
 If you&rsquo;re able to do some TCPdump at the 3rd party firewall, most likely, you will see the packets arriving there usually. What happens is that the router forwards the packet to the computer in question, but it is the computer that drops the packet because the Computer Firewall don&rsquo;t see the packet coming from the same network, so I would recommend you to disable the Computer Firewall and ping again, most likely that would be the issue, if that is the issue and you don't want to disable the Computer Firewall, you might need to Masquerade the traffic as it leaves the interface where the computer is connected to, so the computer sees it as coming from the same network. 
 Regards,

IPSec VPN TELTONIKA RUT240 and SOPHOS XGS

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