WAN disconnect issue RT-AX88U 386.1_2 merlin

[MrRederick]

Hi all,

I am confused on this one. I rebooted my AX88U last night, and this morning went to work.
Came home to find a red WAN light, and trying to access any web pages from my desktop PC gave me a message "your WAN Ethernet cable is disconnected".
Checked the link lights between ASUS and my cable modem (Virgin Media UK Hub 3) and link lights were on. Using my 4G LTE connection I was able to ping the WAN IP of AX88U.
SSH'd onto the router and confirmed the WAN IP on eth0 was the one I was pinging. Logged into web interface and dumped the log.
Then unplugged Ethernet cable from the modem, plugged it back in again. Restored outbound web.

What is odd is that modmon was able to update the cable modem stats during the "outage".

So what is it in the ASUS that determines "WAN is down" and how can I debug what it thinks is an outage?

Part of log below.

Thanks!

ar 19 07:38:53 kernel: br0: topology change detected, propagating
Mar 19 07:38:53 kernel: br0: port 4(eth4) entered forwarding state
Mar 19 07:38:56 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link DOWN.
Mar 19 07:38:56 kernel: br0: port 4(eth4) entered disabled state
Mar 19 07:38:59 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link UP at 1000 mbps full duplex
Mar 19 07:38:59 kernel: br0: port 4(eth4) entered listening state
Mar 19 07:38:59 kernel: br0: port 4(eth4) entered listening state
Mar 19 07:39:01 kernel: br0: port 4(eth4) entered learning state
Mar 19 07:39:03 kernel: br0: topology change detected, propagating
Mar 19 07:39:03 kernel: br0: port 4(eth4) entered forwarding state
Mar 19 07:46:07 modmon: Cable modem stats successfully retrieved
Mar 19 07:52:07 WAN_Connection: WAN(0) link down.
Mar 19 08:12:48 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link DOWN.
Mar 19 08:12:48 kernel: br0: port 4(eth4) entered disabled state
Mar 19 08:12:50 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link UP at 10 mbps full duplex
Mar 19 08:12:50 kernel: br0: port 4(eth4) entered listening state
Mar 19 08:12:50 kernel: br0: port 4(eth4) entered listening state
Mar 19 08:12:52 kernel: br0: port 4(eth4) entered learning state
Mar 19 08:12:54 kernel: br0: topology change detected, propagating
Mar 19 08:12:54 kernel: br0: port 4(eth4) entered forwarding state
Mar 19 08:16:08 modmon: Cable modem stats successfully retrieved
Mar 19 08:46:07 modmon: Cable modem stats successfully retrieved
Mar 19 09:16:07 modmon: Cable modem stats successfully retrieved
Mar 19 09:46:07 modmon: Cable modem stats successfully retrieved
Mar 19 10:16:08 modmon: Cable modem stats successfully retrieved
Mar 19 10:46:07 modmon: Cable modem stats successfully retrieved
Mar 19 11:16:06 modmon: Cable modem stats successfully retrieved
Mar 19 11:46:06 modmon: Cable modem stats successfully retrieved
Mar 19 12:16:06 modmon: Cable modem stats successfully retrieved
Mar 19 12:46:06 modmon: Cable modem stats successfully retrieved
Mar 19 13:16:06 modmon: Cable modem stats successfully retrieved
Mar 19 13:46:06 modmon: Cable modem stats successfully retrieved
Mar 19 14:16:06 modmon: Cable modem stats successfully retrieved
Mar 19 14:46:07 modmon: Cable modem stats successfully retrieved
Mar 19 15:16:07 modmon: Cable modem stats successfully retrieved
Mar 19 15:46:07 modmon: Cable modem stats successfully retrieved
Mar 19 16:16:07 modmon: Cable modem stats successfully retrieved
Mar 19 16:46:07 modmon: Cable modem stats successfully retrieved
Mar 19 17:16:06 modmon: Cable modem stats successfully retrieved
Mar 19 17:46:06 modmon: Cable modem stats successfully retrieved
Mar 19 18:16:07 modmon: Cable modem stats successfully retrieved
Mar 19 18:46:07 modmon: Cable modem stats successfully retrieved
Mar 19 19:03:56 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link DOWN.
Mar 19 19:03:56 kernel: br0: port 4(eth4) entered disabled state
Mar 19 19:04:01 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link UP at 1000 mbps full duplex
Mar 19 19:04:01 kernel: br0: port 4(eth4) entered listening state
Mar 19 19:04:01 kernel: br0: port 4(eth4) entered listening state
Mar 19 19:04:03 kernel: br0: port 4(eth4) entered learning state
Mar 19 19:04:05 kernel: br0: topology change detected, propagating
Mar 19 19:04:05 kernel: br0: port 4(eth4) entered forwarding state
Mar 19 19:04:10 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link DOWN.
Mar 19 19:04:10 kernel: br0: port 4(eth4) entered disabled state
Mar 19 19:04:13 kernel: eth4 (Ext switch port: 3) (Logical Port: 11) (phyId: b) Link UP at 1000 mbps full duplex
Mar 19 19:04:13 kernel: br0: port 4(eth4) entered listening state
Mar 19 19:04:13 kernel: br0: port 4(eth4) entered listening state
Mar 19 19:04:15 kernel: br0: port 4(eth4) entered learning state
Mar 19 19:04:17 kernel: br0: topology change detected, propagating
Mar 19 19:04:17 kernel: br0: port 4(eth4) entered forwarding state
Mar 19 19:16:07 modmon: Cable modem stats successfully retrieved
Mar 19 19:18:24 dropbear[24955]: Child connection from 192.168.1.13:50521
Mar 19 19:18:40 dropbear[24983]: Password auth succeeded for 'admin' from 192.168.1.13:50535
Mar 19 19:18:40 PTCSRV: [SSH] login succeeded from 192.168.1.13 after 1 attempts
============
Unplugged & reconnected Ethernet to modem
============
Mar 19 19:21:25 kernel: eth0 (Int switch port: 3) (Logical Port: 3) (phyId: c) Link DOWN.
Mar 19 19:21:29 WAN_Connection: ISP's DHCP did not function properly.
Mar 19 19:21:32 kernel: eth0 (Int switch port: 3) (Logical Port: 3) (phyId: c) Link UP at 1000 mbps full duplex
Mar 19 19:21:34 WAN_Connection: WAN(0) link up.
Mar 19 19:21:34 rc_service: wanduck 999:notify_rc restart_wan_if 0

 

[RMerlin]

According to this the Ethernet connection went down between the modem and the router. This usually indicate that the modem rebooted itself. After that reboot, you ended up with a DHCP lease from your modem's internal DHCP server rather than from your ISP.

 

[MrRederick]

According to this the Ethernet connection went down between the modem and the router. This usually indicate that the modem rebooted itself. After that reboot, you ended up with a DHCP lease from your modem's internal DHCP server rather than from your ISP.

Interesting - I have an uptime of 11 days on the modem, but I don't trust it. I will reboot it manually, and if it happens again call the cable firm.

Thanks!