WNDR3700 Gigabit WAN No Link

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g12345
Posts: 10
Joined: Tue Mar 06, 2012 9:09 pm

WNDR3700 Gigabit WAN No Link

Post by g12345 »

Hello all, long time user here. Been going along great but my modem decided to die on me so I had Comcast swap it for a new one. The new one is the same model, but it seems to connect gigabit now which I never noticed before. It works fine in the stock firmware, but every version of Gargoyle that I tried, there would be no link between the devices, the ethernet light on the modem goes out, the wan light on the router blinks very slowly. While booting it up my modem shows a link light until about 20 seconds into the boot process when it goes out and won't connect anymore. Does Gargoyle not support gigabit on the WAN side? I put a 10/100 switch in between the devices and everything works fine. I tried this on 2 different 3700s, a v1 and a v2 and both do the same thing. It seems they won't negotiate the gigabit link with Gargoyle. Is there some command line I could run that changes the config of the port? Is the WAN side ETH0 or ETH1?

g12345
Posts: 10
Joined: Tue Mar 06, 2012 9:09 pm

Re: WNDR3700 Gigabit WAN No Link

Post by g12345 »

Been researching this, seems like if I force the WAN side to negotiate at 100 mbit it should solve the issue. I found these instructions, anyone see any possible issues with it running on Gargoyle (they are generic for openwrt):

I found that my UnityMedia supplied Cisco EPC3212 cable modem doesn't play nice with the WNDR3700v2's Gigabit ethernet hardware. Here's my workaround. It reduces the WNDR3700v2's "wan" (eth1 here) interface speed to just 100Mbit. See the ethtool manual for details.

1. Install ethtool

opkg update
opkg install ethtool

2. Create, edit, and save /etc/init.d/ethtool so it reads:

#!/bin/sh /etc/rc.common
# Copyight (C) 2006 OpenWrt.org
START=41
start() {ethtool -s $(uci -P/var/state get network.wan.ifname) speed 100 duplex full autoneg off}
stop() {ethtool -s $(uci -P/var/state get network.wan.ifname) speed 1000 duplex full autoneg off}

3. Set it up and use it:

chmod 0755 /etc/init.d/ethtool
cd /etc/rc.d
ln -s ../init.d/ethtool S41ethtool
/etc/init.d/ethtool start

scribbles
Posts: 1
Joined: Sat Nov 03, 2012 2:15 pm

Re: WNDR3700 Gigabit WAN No Link

Post by scribbles »

https://dev.openwrt.org/ticket/10517

Note that this problem still exists out of the box...

For anyone that comes along and can't install ethtool because of the bug:

Login to your WNDR3700v2 and disable WAN, DHCP, and set a static IP. Plug the WNDR3700v2 into a network port on the functional router and turn it on. SSH to the static IP you set. You now can install ethtool using the upstream router. Follow the instructions above, note that the code pasted funny and will error if you don't space it properly. If the last line runs without error, you're done. Re-enable WAN and DHCP. Plug everything back as it should be with the WNDR3700v2 as the main router and powercycle the network devices.

zigal
Posts: 1
Joined: Wed Sep 28, 2016 1:59 pm

Re: WNDR3700 Gigabit WAN No Link

Post by zigal »

g12345 wrote:Been researching this, seems like if I force the WAN side to negotiate at 100 mbit it should solve the issue. I found these instructions, anyone see any possible issues with it running on Gargoyle (they are generic for openwrt):

I found that my UnityMedia supplied Cisco EPC3212 cable modem doesn't play nice with the WNDR3700v2's Gigabit ethernet hardware. Here's my workaround. It reduces the WNDR3700v2's "wan" (eth1 here) interface speed to just 100Mbit. See the ethtool manual for details.

1. Install ethtool

opkg update
opkg install ethtool

2. Create, edit, and save /etc/init.d/ethtool so it reads:

#!/bin/sh /etc/rc.common
# Copyight (C) 2006 OpenWrt.org
START=41
start() {ethtool -s $(uci -P/var/state get network.wan.ifname) speed 100 duplex full autoneg off}
stop() {ethtool -s $(uci -P/var/state get network.wan.ifname) speed 1000 duplex full autoneg off}

3. Set it up and use it:

chmod 0755 /etc/init.d/ethtool
cd /etc/rc.d
ln -s ../init.d/ethtool S41ethtool
/etc/init.d/ethtool start
So I've follow instructions exactly, but I get this error when entering "/etc/init.d/ethtool start" :

root@Gargoyle-Laj:/etc/init.d# /etc/init.d/ethtool start
/etc/rc.common: line 138: {ethtool: not found

I'm running Gargoyle 1.8.1 on WNDR3700v4. The original problem is that when restarting (ie with watchdog), the router seems incapable of negociating connection with the cable modem (tested OK with other router) and getting a wan ip. Then if I restart the modem, the router get a Wan ip. But i'll get the same problem when the scheduled restart of the router occur. No linux knowledge at all.

So, do you know how to fix the original problem or the script?

Thanks

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