AXC F 2152 loses network connection after changing IP address

PLCnext Technology & PLCnext Controls
1

Hello everyone,
I’m experiencing a strange issue with my PLCnext AXC F 2152.
Whenever I change the device’s IP address (either via WBM or PLCnext Engineer or SSH), the controller immediately becomes unreachable on the network.
After that:
The PLC does not respond to ping

  • .
  • It doesn’t appear with any IP address on the network.
  • In Wireshark , I can only see LLDP packets from the controller (e.g. Port Status = OFF).
  • → So the interface seems physically active but software-disabled.
  • Environment:
    Device: AXC F 2152
  • Firmware: 2024.6.1
  • PLCnext Engineer version: 2024.6
  • Connection: LAN1 (eth0)
  • Method of change: [WBM / PLCnext Engineer / SSH]
  • Question:
    Is this a known issue or configuration bug?
  • How can I reliably change the IP address without losing connectivity?
  • Is there a recommended way to reset or verify the network configuration after IP changes?

Thanks a lot for your help!

Best regards,
Josef

2

Hi Josi,
can you try to clear your arp table and see if that works? That helped me in the past when I faced that issue.
Commandline → arp -d

BR
DivisionByZero

3

Hi DivisionByZero,

thanks a lot for the „arp -d“ tip!

  1. I logged in as admin via SSH,
  2. switched to root user using su
  3. ran ip neigh flush all (as an alternative to arp -d)
  4. changed the IP address via WBM

Now it works, the controller is reachable under its new IP address.

Thank you!

BR

4

Forgot to mention that you have set a root password before switching to su:

  1. I logged in as admin via SSH,
  2. set root password using sudo passwd root
  3. switched to root user using su
  4. ran ip neigh flush all (as an alternative to arp -d)
  5. changed the IP address via WBM

Now it works, the controller is reachable under its new IP address.

Thank you!

BR