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ZD1200 and T310D not interlocked

New Contributor


This occurred during the process of connecting T310D to ZD1200.

After the AP is linked to the controller, it receives a firmware upgrade and reboots, and the AP state on the controller is disconnect.

And the same symptoms repeat over and over again and again.

What should I check?

ZD1200 ver.

AP T310D

The peculiarity is that it is a closed network that is not connected to the external Internet.

Thank you.




Some factors which may be causing failure.

  • AP and ZD is on different site/network and reaching each other over VPN. Due to path MTU issues, configuration update might be failing. To fix the issue, go to ZD >> Access points >> reduce the MTU size from 1500 to 1400 or 1200 etc.
  • Login AP CLI and check if upgrade is successful or not. 

get version

  • Check AP syslog for any error or failures.

get syslog log

  • Try to ping the ZD IP from AP and see if ping is constant and not dropping.

Syamantak Omer | Community moderator | Sr.Staff TSE | CWNA | CCNA | RASZA | RICXI

Hi Syamantak,

As your say MTU size was lowered to 1200, but the result was the same.

Symptoms appear as disconnect in the controller status window after the first firmware upgrade, firmware upgrade appears again after reboot and the symptoms continue to be repeated.

The firmware has not been upgraded, and the AP has not been contacted due to continuous reboot.

We tried new equipment and the result was the same.



Before lowering the MTU size, we first need to know if AP-ZD are communicating over a VPN or not. If you are not using VPN, I do not think this as path MTU issue.

I have also provided you the syslog command to see if you can find any error.

If you are unable to figure out, please open a support case.

Syamantak Omer | Community moderator | Sr.Staff TSE | CWNA | CCNA | RASZA | RICXI