Zyxel - VMG4005-B50A - Support & Info

[GeminiServer]

The default admin user currently faces issues retrieving xdslctl information via SSH or Telnet. The console does not respond as expected.

When using the go-dsl tool, the xdslctl process fails to respond and is not properly terminated by the firmware on the Zyxel VMG4005-B50A. This problem occurs during both connection and disconnection attempts, leading to orphaned xdslctl processes.

Repeated connection attempts result in an increasing number of orphaned xdslctl processes. This accumulation causes CPU and RAM usage to reach 100%, ultimately leading to a situation where only a reboot will restore the modem to a functional state.

To avoid this issue, use the root or supervisor account (which are the same), as this problem does not occur with these higher-level privileges.

Root/supervisor password?

1. To optain the root password contact Zyxel support, as I did!
2. Or use this tool to get the default root password!
3. https://github.com/boginw/zyxel-vmg8825-keygen

`python3 main.py #THE_S#_OF_THE_MODEM'
Password is: zcfgBeCommonGenKeyBySerialNumMethod3 : xxxxxxxxxx

Using user: root/supervisor on a VMG4005-B50A*

* It appears that the DSLAM has switched to compatibility mode because I performed too many resyncs.

[janh]

Thank you for the report!

Does the same issue exist, when connecting using a normal Telnet or SSH client? When using the tool, does it happen for both Telnet and SSH?

I assume the most likely reason here, is that the admin login leads to the Zysh shell, while root and superuser allow access to a proper shell.

If there is an easy fix to make it work with Zysh, I'd like to implement that, otherwise I'm going to add a note to the documentation.

• It appears that the DSLAM has switched to compatibility mode because I performed too many resyncs.

Considering the minimum line in the SNR graph, there could also be an actual issue on the line. Maybe some issue with vectoring?

[GeminiServer]

Does the same issue exist, when connecting using a normal Telnet or SSH client? When using the tool, does it happen for both Telnet and SSH?

No, with the normal SSH/Telnet client/console I'm able to request the xdslctl also as a default admin user.
And yes, with the tool, does not matter if I choose Broadcom SSH or Telnet.

If there is an easy fix to make it work with Zysh, I'd like to implement that, otherwise I'm going to add a note to the documentation.

I'm not sure if there is a hard or easy fix. I really do not know how the console part is implemented, but you are right, the non-root user will see the ZySH>.

Considering the minimum line in the SNR graph, there could also be an actual issue on the line. Maybe some issue with vectoring?

Mmmm, I'm not sure. Before I bought and used the Zyxel modem, I had the Vigor165 installed. It always had ~250 Mbps and higher sync (for the past 2-3 years). However, the Vigor kept rebooting and was probably defective in last time, as I had been using it for over 4 years. Before exchanging it, i tried different firmware versions for the Vigor, and after too many firmware changes and syncs in a short time, the VDSL sync dropped directly to 204 Mbps. So, I switched to the Zyxel modem. I think I need to wait a few weeks before the DSLAM goes back up to the maximum again... that's what I'm hoping for....