IPSec-VPN with NAT

Hi all,

I just created a new Site-to-Site-VPN with IPSec and the VPN is UP.

If I log into my Firewall and try to ping the private IP on the other party, it works, if I try to do that from my PC it does NOT work...

The VPN should use two private IPs, one by us (10.0.16.1) and the other by the other party (172.27.10.70). The other party needs all packets arrive from 10.0.16.1.

As I said from the firewall I can ping 172.27.10.70. The other party (172.27.10.70) can ping the firewall IP (10.0.16.1), but from my PC I can just ping the firewall's IP (10.0.16.1) but not the remote one (172.27.10.70).

If I start a tcpdump on the firewall I see that:

tcpdump -i lag0.51 host 10.0.51.198 and host 172.27.10.70

15:51:46.848520 IP 10.0.51.198 > 172.27.10.70: ICMP echo request, id 18322, seq 622, length 64
15:51:47.850407 IP 10.0.51.198 > 172.27.10.70: ICMP echo request, id 18322, seq 623, length 64

Any idea where I can check why it does not work? The other party says, no packet come from the VPN if I ping from my PC (but if I ping from the firewall)...

I'm using Sophos UTM9 with Firmware 9.413.4.

Thanks a lot for your help

Luca