NAT Loopback not working if network is not directly connected to ZyWall 110

IlyaTaskaev

Network scheme listed below:



1:1 NAT

Task: Ping Server from the local network (172.19.1.30) by Public IP: 99.99.99.99.



Internet is working, 

When I ping it from my Laptop I got "Request timed out" error.

Source IP: 172.19.1.30
Dest IP:  99.99.99.99

Policy rules added with maximum rights allowed from anywhere to the server IP 172.19.0.21.

I tried packet capture on 172.19.0.21 server, and I see packets from my laptop, but it comes from 172.19.99.2 IP, therefore NAT is working:



Seems ZyWall does not revert back the original source IP address (172.19.1.30) to the packet and not resend it back to my Laptop according to static route? Is this design restrictions?

When I ping it from HP router ping is successful.

For any directly connected to ZyWall network, it works perfectly, but for Network, which needs to be routed it doesn't work.

IlyaTaskaev

Hey, this little boi resolves the issue

Now it works perfectly, thank you for the suggestion to update firmware. 

Zyxel_Stanley

Hi @IlyaTaskaev

Which firmware is working on your ZyWALL110?

Can you capture the ICMP packets on interface 172.19.99.2?

IlyaTaskaev

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?

Zyxel_Stanley

Hi @IlyaTaskaev

We have fixed similar issue in official firmware.

Can you upgrade to 4.33 firmware first and try it again?

Avoids configuration issue in upgrading process, you can forward your configuration to me by private message. I can help to verify it first,

IlyaTaskaev

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

IlyaTaskaev

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.

Zyxel_Stanley

Hi @IlyaTaskaev

I will send private message to you for check this issue more details.

IlyaTaskaev

Hey, this little boi resolves the issue

Now it works perfectly, thank you for the suggestion to update firmware. 

Zyxel_Stanley

Hi @IlyaTaskaev
It's good to know your issue has resolved.