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ER8411 frequently disconnects from internal network

ER8411 frequently disconnects from internal network

ER8411 frequently disconnects from internal network
ER8411 frequently disconnects from internal network
2025-05-22 05:04:57 - last edited 2025-05-22 09:55:36
Tags: #DHCP Service #Network Connectivity
Model: ER8411  
Hardware Version: V1
Firmware Version: 1.2.2 Build 20240809 Rel.48592

We recently deployed an ER8411 unit. Since installation, we’ve observed intermittent disconnections from the internal network — typically 1 to 6 request timeouts  before auto-recovery. I chekced System Log and analysis indicates the issue coincides with DHCP lease assignments. Specifically, the event occurs when the ER8411 DHCP server assigns an IP (x.x.x.x) to a client with MAC address x.x.x.x..
 

Please advise if this behavior could be linked to a known firmware bug, DHCP service instability, or configuration issue. Appreciate any recommendations on tuning, firmware updates, or potential hardware issue ?

Thank you

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#1
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1 Accepted Solution
Re:ER8411 frequently disconnects from internal network-Solution
2025-05-22 09:55:15 - last edited 2025-05-22 09:55:36

Clive_A

 

We have identified the root cause of the issue — a faulty LAN cable. This cable caused signal instability, which in turn affected the performance of the network switch and led to intermittent disconnections across connected devices.
 

This behavior is likely related to the nature of DHCP lease assignments, which involve multiple broadcast and unicast packets exchanged between the DHCP server (on the ER8411 router) and client devices. The faulty cable introduced intermittent link issues or packet loss during these exchanges, disrupting the DHCP handshake process and causing temporary network instability or timeouts across the network switch.
 

Thank you for your attention and support.

 

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Re:ER8411 frequently disconnects from internal network
2025-05-22 06:27:58

  @K_Liew 

There is no known behavior like this.

The information provided is not enough to determine what happened.

What device experiences the issue? There is no description about it.

The log, does it(MAC) relate to the device that experiences the issue?

What basic steps did you take to verify the physical link?

Wireshark for DHCP to see if there is a problem with the DHCP assignment to the troubled device?

How Does DHCP Work? Common Questions and Solutions

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Re:ER8411 frequently disconnects from internal network
2025-05-22 07:36:44 - last edited 2025-05-22 07:39:03

  @Clive_A 

Thank you  for your replied.
 

1. Devices Experiencing the Issue
- this includes Wi-Fi access points and all computers connected via LAN. These devices are connected to a TP-Link TL-SG3428 network switch, which is uplinked to the TP-Link ER8411 VPN router. Our previous router, which was also connected to the TL-SG3428 switch, did not have this issue and operated smoothly.
 

2. Scope of the Issue
- The issue affects all devices, wired (LAN) and via wireless AP clients experience temporary disconnection. All in same subnet (only 1 subnet in our office.)

- Disconnections typically result in 1 to 6 request timeouts ping to P-Link ER8411 , after which connectivity resumes automatically.

- The issue is not always tied to the same MAC address, but the System Log consistently shows DHCP assignment notices (e.g., “DHCP server assigns an IP to MAC x.x.x.x”) around the exact time of these disconnections.

 


3. System Log Observation
- There are no warnings or errors in the System Log or DHCP Log.

- However, when the disconnection occurs (as confirmed by ping request timeouts), the System Log shows a DHCP assignment event at or just before the outage window. This behavior has been consistent across several observed instances.
 

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#3
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Re:ER8411 frequently disconnects from internal network-Solution
2025-05-22 09:55:15 - last edited 2025-05-22 09:55:36

Clive_A

 

We have identified the root cause of the issue — a faulty LAN cable. This cable caused signal instability, which in turn affected the performance of the network switch and led to intermittent disconnections across connected devices.
 

This behavior is likely related to the nature of DHCP lease assignments, which involve multiple broadcast and unicast packets exchanged between the DHCP server (on the ER8411 router) and client devices. The faulty cable introduced intermittent link issues or packet loss during these exchanges, disrupting the DHCP handshake process and causing temporary network instability or timeouts across the network switch.
 

Thank you for your attention and support.

 

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