ZyWall USG 50 L2TP Remote Acces (Server role) behind Asus RT-AC57U as DMZ but can not connect

pepev82 Posts: 2
First Anniversary Friend Collector First Comment
edited April 2021 in Security
Hi all,

I seen all the ytd videos about Zyxel USG/VPN behind NAT config, but there is always one or two things which is not in my ZyWALL USG 50. e.g. : Quick Setup -> You have 3 options on the video, cool, but I have only 2, and yeah, I wish to setup the 3rd one, L2TP VPN. I wish to access my home network from 2 iOS device.
I just copied all the settings, step-by-step, (except IP addresses) from a working enivroment where the device is Zyxel VPN 100, and I can connect from my iOS built in client.
Zyxel USG 50 - Firmware 3.30(BDS.9)
Boot module: 1.17

(Internet) dynamic but public IP from ISP (same on myip.com as on my router WAN IP) --> Asus RT-AC57U pppoe -> static IP in DMZ zone -> USG50 WAN

Any idea more than appreciated.



All Replies

  • Zyxel_Can
    Zyxel_Can Posts: 342  Zyxel Employee
    Friend Collector First Answer First Comment
    edited March 2021

    Hi @pepev82,


    For L2TP settings you can take following KB article as reference;



    The steps in the KB article, is the equivalent of the 3rd option in the Quick Setup.

     Please kindly try to configure your USG50 as in the article.

     After creating L2TP option, you can apply NAT settings.


    Best regards.
  • pepev82
    pepev82 Posts: 2
    First Anniversary Friend Collector First Comment
    Dear @Zyxel_Can

    Thank you for your answer.

    Since posted my question, i just go forward to look around on Zyxel forum.

    Then i found @Zyxel_Emily 's answer to someone else.

    where she said:

    "ZyWALL USG 50 does not support L2TP server behind NAT.

    L2TP server behind NAT is supported since firmware version 4.11.

    You may consider USG60/USG110/ATP100/USG FLEX 100 which supports this scenario."

    So I just sold my USG50 and hopefully soon i will buy a Zyxel USG60 device.

    Certainly, I just saved that PDF which could be very useful to setup my new device.

    Best wishes,


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