When creating 1:1 NAT rules for local hosts, these local hosts become unreachable through VPN IPSec.

Zyxel_Charlie

The virtual server function is a "port forwarding" function. 

The 1:1 NAT function is "forwarding all traffic" to the local server. 

When using "1:1NAT", the traffic can't pass through to the tunnel because all traffic passes through the WAN interface.

In "packet flow explore", the priority of 1-1 SNAT is higher than site to sitesite-to-site VPN when 1:1 NAT is enabled.

 

To solve this problem, please reorganize the order of the routing priority.

For legacy models with ZLD 3.30 platform, use the following CLI command.

ip route control-virtual-server-rules activate

 

For new USG/ZyWALL series with ZLD 4.13, enable "Use Static-Dynamic Route to Control 1-1 NAT Route" on GUI.

Then the priority of Site To Site VPN becomes higher than 1-1 NAT route.