IPSEC VPN with SNAT in a little subnet

enzopa

HI,
I created a site-to-site IPSEC VPN with SNAT.
Everything works fine until I use an x.x.x.x/24 subnet, but when I try to use an x.x.x.x/27 the ping no longer works.
For the configuration I used this guide:
https://mysupport.zyxel.com/hc/en-us/articles/360003321659--ZyWALL-USG-How-to-configure-VPN-SNAT-on-Zyxel-gateways

But that refers to a /24 subnet.
Where am I wrong?

PeterUK

I have a setup like this it make hard time working out problems.

On Outbound Traffic source NAT you have source subnet the same size as SNAT? And changed Destination NAT?

enzopa

Hi @PeterUK ,

Thanks, you pointed me in the right direction.
In the Destination NAT under Mapped iP I had selected the /24 subnet.
it was enough to put /27 there and now everything works.
Thanks again.

PeterUK

I have a setup like this it make hard time working out problems.

On Outbound Traffic source NAT you have source subnet the same size as SNAT? And changed Destination NAT?

enzopa

Hi @PeterUK ,

Thanks, you pointed me in the right direction.
In the Destination NAT under Mapped iP I had selected the /24 subnet.
it was enough to put /27 there and now everything works.
Thanks again.