ISP's DHCP did not function properly./WAN LED off

[Rob Novak]

Hello all. I know that at first sight you'll think I didn't read or search through the forum, but I have. Exhaustively.

I've got an RT-AC68U that works great with Merlin's latest firmware and stock firmware except for the error in the subject. It seems like when it tries to renew the DHCP lease from Comcast, it get that message AND the WAN indicator on the router goes off.

I thought it may have been an issue with my older SBG-6782 modem in bridge mode, so I went to Walmart and purchased an SB-6183. It was active for almost 24 hours without an issue, but when I got home from work I noticed I had no internet connection on my phone. Sure enough, the WAN light was off.

Sometimes I can disconnect the ethernet cable from the WAN port and plug it back in to make it work. If I unplug the cable from the modem and plug it back in, the WAN light stays off. Sometimes I power cycle the modem, and the WAN port doesn't come back on. Again, unplugging/plugging back in on the router seems to make it kick on.

System logs show nothing happening today until these three lines at the very end of the log, with one prior and one when I woke the PC from sleep:

Jul 30 07:13:59 roamast: eth1: add client [my PC on LAN1] to monitor list (left for work around here)
Jul 30 16:05:16 WAN_Connection: ISP's DHCP did not function properly.
Jul 30 16:05:17 nat: apply redirect rules
Jul 30 16:05:21 WAN_Connection: Ethernet link down.
Jul 30 18:06:09 roamast: eth1: add client [my PC on LAN1] to monitor list (PC out of standby at this time)

WAN light went off while typing this message... from here on is what just happened:

ifconfig while WAN light is off:
eth0 Link encap:Ethernet HWaddr xx:xx:xx:xx:xx:xx
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:6373875 errors:0 dropped:0 overruns:0 frame:0
TX packets:4291476 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3373327038 (3.1 GiB) TX bytes:3206335016 (2.9 GiB)
Interrupt:179 Base address:0x4000

Power cycling after the disconnect results in the WAN light not illuminating even though LAN1 and LAN2 are on almost immediately. Unplugging/pluggin in right after boot made the WAN light illuminate.

ifconfig after restored:
eth0 Link encap:Ethernet HWaddr xx:xx:xx:xx:xx:xx
inet addr:73.xxx.xxx.xxx Bcast:73.xxx.xxx.255 Mask:255.255.248.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:7716 errors:0 dropped:0 overruns:0 frame:0
TX packets:9478 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:3222412 (3.0 MiB) TX bytes:5709717 (5.4 MiB)
Interrupt:179 Base address:0x4000

Log messages at the time this occured:
Jul 30 18:47:41 WAN_Connection: ISP's DHCP did not function properly.
Jul 30 18:47:42 nat: apply redirect rules
Jul 30 18:47:46 WAN_Connection: Ethernet link up.
Jul 30 18:47:46 rc_service: wanduck 204:notify_rc restart_wan_if 0
Jul 30 18:47:47 miniupnpd[8709]: ioctl(s, SIOCGIFADDR, ...): Cannot assign requested address
Jul 30 18:47:47 miniupnpd[8709]: Failed to get IP for interface eth0
Jul 30 18:47:47 miniupnpd[8709]: SendNATPMPPublicAddressChangeNotification: cannot get public IP address, stopping
Jul 30 18:47:47 kernel: Attempt to kill tasklet from interrupt
Jul 30 18:47:56 WAN_Connection: Ethernet link down.

I disabled uPNP after seeing this.

Any ideas?

 

[john9527]

The ethernet link between the modem and router is dropping/having errors. Get out a flashlight and check the ethernet ports on the modem/router for any bent pins/dirt, and try a new cat5e or cat6 cable.

 

[Rob Novak]

Thanks for the response. The modem is brand new out of the box, and the second one I'm using. The WAN port pins are in perfect condition and I previously replaced the cable with that though.

To add to my original post, I received the router on Thursday and have been dealing with this issue daily since then.

 

[ColinTaylor]

That would indicate that it's a hardware fault with the router. Probably the WAN socket is not soldered properly onto the PCB creating an intermittent connection. Get a replacement.

 

[RMerlin]

Also, a cable modem having sync issues might reboot itself, which would also cause the Ethernet link to go down for a few seconds.

 

[Rob Novak]

I went and purchased a new RT-AC1900U and reconfigured the AC68U as an aimesh node. No issues at all in this configuration.