IlyaTaskaev

Hey, this little boi resolves the issue Now it works perfectly, thank you for the suggestion to update firmware. 

Hi! I have updated my ZyWall to the latest firmware: System Name:zywall-110 Model Name:ZyWALL 110 Serial Number:S152L51400338 MAC Address Range:04:BF:6D:1A:29:CD ~ 04:BF:6D:1A:29:D3 Firmware Version:V4.33(AAAA.0) / 2019-01-09 09:37:31 The issue is still here, updating firmware not helped me.

We need to plan downtime to do it, thank you again, I will update this thread as soon as we update firmware 

Stanley, thank you for your reply! >Can you capture the ICMP packets on interface 172.19.99.2? I think ZyWall have the ability to capture traffic, I need to try it. My Firmware Version: V4.20(AAAA.2) / 2016-11-22 19:04:14, not latest, but, do you think it can affect NAT?