ZyWALL USG 20 can't connect to console

Options
mcbsys
mcbsys Posts: 4
Friend Collector
in Security
Hi,

I've inherited a ZyWALL USG 20 and don't have the password. I found password reset instructions on the European forum here. However, that requires console access, which I have been unable to establish.

I'm  trying 115200 baud, 8 data bits, 1 stop bit, no parity, no flow control as documented in the CLI Reference Guide. I've tried a USB serial cable with an FTDI chip (connected to a laptop) as well as a standard COM cable (connected to a server with a plain old COM1 port). I've restarted the ZyWALL multiple times. No matter what I do, I get a black screen in Putty or TeraTerm.

The Reference Guide says:

• Garbled text displays if your terminal emulation program’s speed is set lower than the ZyWALL’s.
• No text displays if the speed is set higher than the ZyWALL’s.
• If changing your terminal emulation program’s speed does not get anything to display, restart the
ZyWALL.
• If restarting the ZyWALL does not get anything to display, contact your local customer support

So I'm on the last step:  contacting you all, my "local customer support."

Any thoughts on how to get access to this device? I don't suppose a short press on the Reset button would reset just the password? I'd like to see how it's configured before doing a factory reset and starting from scratch.

Thanks for any tips!

All Replies

  • Zyxel_Cooldia
    Zyxel_Cooldia Posts: 1,455  Zyxel Employee
    First Anniversary 10 Comments Friend Collector First Answer
    Options
    Hi @mcbsys,

    Press reset button will reset to system default, not just only admin password. You need to set up start from scratch. Can you check Device Manager if the COM port maps to COM1?
  • mcbsys
    mcbsys Posts: 4
    Friend Collector
    edited May 2022
    Options
    @Zyxel_Cooldia, thanks for your reply.
    In Device Manager on my laptop, the USB cable usually shows up as COM5. I adjusted PuTTY and TeraTerm to COM5, but still got a black screen. On the server, the direct COM port cable shows up as COM1 in Device Manager. PuTTY was set to COM1, but still I got the black screen.
  • mcbsys
    mcbsys Posts: 4
    Friend Collector
    Options
    I gave up and did a factory reset. The console still doesn't work.
  • Zyxel_Cooldia
    Zyxel_Cooldia Posts: 1,455  Zyxel Employee
    First Anniversary 10 Comments Friend Collector First Answer
    Options
    Hi @mcbsys,

    Not sure if it is physical serial port issue. Maybe you can try to attach console line to other device to see if it have anything output.
  • mcbsys
    mcbsys Posts: 4
    Friend Collector
    Options
    Well, the same cable works fine with three Cisco switches. Maybe it's the physical port.
  • TedB
    TedB Posts: 3
    First Comment
    Options

    I just posted a question regarding the same type of issue. I got to the Putty black screen but no throughput to access the GUI console. The articles seem to be incomplete.

  • Zyxel_Emily
    Zyxel_Emily Posts: 1,298  Zyxel Employee
    First Anniversary 10 Comments Friend Collector First Answer
    Options

    Hi @TedB,

    On your laptop/PC, go to Device Manager and check which COM port is. Enter the correct COM port and speed 115200 in PuTTY.

    Make sure you connect an USB serial cable to the console cable.

    image.png
    image.png
    image.png

Categories

Security Highlight


Read more

Security Help Center

EnglishTiếng ViệtРусскийไทย中文（台灣）