Upgraded USG1100 to latest firmware and DHCP server stopped working on reboot

imaohw Posts: 124  Ally Member
First Anniversary 10 Comments Friend Collector First Answer
edited April 2023 in Security

I upgraded my USG1100 to V4.73(AAPK.1). Upon reboot after upgrade the system appeared to come up normally but no devices could get IP addresses from the USG DHCP server. Not on any lan or Vlan.

This used to happen on older versions of firmware but has not been happening for a while.

The “fix” that seems to work is to edit one of the DHCP configurations (ie change pool size for one lan or Vlan) and then click ok. Immediately the USG starts serving IP addresses for all lans and vlans.

Let me know what information I can provide to help diagnose this issue.

All Replies

  • Zyxel_Jeff
    Zyxel_Jeff Posts: 1,099  Zyxel Employee
    First Anniversary 10 Comments Friend Collector First Answer
    edited May 2023

    Hi @imaohw
    Could you please let me know what your previous firmware version was that ran stably? Also, when you notice that the DHCP server has stopped assigning IP addresses, please collect the following information for us:
    (1). Navigate to Maintenance > Diagnostics > Controller and click on "Collect Now" to collect the diag-info log.
    (2). Navigate to Monitor > Network Status > DHCP Table > check the DHCP table
    (2). Run the CLI command "show ip dhcp server status".
    (3). Run the CLI command "show arp-table".

    Thank you.

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