Internet connection using USB-modem stopped working on RT-AC56U

[pauligrinder]

Hello,

I don't what's going on with my router. I was at the hospital for a week (no illness, my daughter was born ), and when I returned, I noticed that my internet connection was down. I tried all the usual stuff - rebooted the router, disconnected and reconnected everything, updated to the latest firmware (was 380.56, now updated to 380.59), but nothing helped. The web interface shows that the connection is up, it gets an IP that looks valid and the auto detected DNS servers are correct, but it just won't get any outside contact. I had similar issues with an older firmware a long time ago - that was a routing issue, ssh'ing into the router and pinging google from there worked, and after a reboot the routing solved itself - but now even that doesn't work. The USB modem is working nicely too, I just tested it on my PC, so the problem is clearly in the router.

Another issue I'm having is that my 5G WiFi doesn't start up every time I reboot the router. It could just be taking a while to start though.

Anyways, any help would be greatly appreciated!

 

[L&LD]

Did your home take a lighting hit or other major power surge while you were in the hospital?

How long did you power everything down for (I would try at least 30 minutes and preferably over an hour) with the AC plug actually pulled from the wall for all networking devices you have.

Congratulations on the new baby girl! At least you have something to keep you occupied while the issue is fixed.

 

[pauligrinder]

Did your home take a lighting hit or other major power surge while you were in the hospital?

Not that I know of, and all my network devices are connected to a surge protected power strip, so I don't think that's the case. Also, I don't have a wired internet connection, so there's no chance of a surge coming through the phone lines. (I've had that too at my parent's place)

How long did you power everything down for (I would try at least 30 minutes and preferably over an hour) with the AC plug actually pulled from the wall for all networking devices you have.

It might have been powered down for 10min or something while I reconnected the cables, I thought that would be enough. Now I left it off over night with the AC adapter unplugged, let's see if that helps.

One thing I noticed yesterday is that the clock of the router keeps going back to 1. august 2015. Once I set the date manually using data --set, it managed to set up my ddns, but connections still didn't work otherwise. Weird ...

 

[charlie2alpha]

Not that I know of, and all my network devices are connected to a surge protected power strip, so I don't think that's the case. Also, I don't have a wired internet connection, so there's no chance of a surge coming through the phone lines. (I've had that too at my parent's place)



It might have been powered down for 10min or something while I reconnected the cables, I thought that would be enough. Now I left it off over night with the AC adapter unplugged, let's see if that helps.

One thing I noticed yesterday is that the clock of the router keeps going back to 1. august 2015. Once I set the date manually using data --set, it managed to set up my ddns, but connections still didn't work otherwise. Weird ...

The clock going back is normal, unless it gets an internet connection to retrieve the current time it will always default to this time. These routers not have a real time clock circuit, they rely on internet time servers.

For the rest of your issues, I can only comment on the 5Ghz WiFi, if you have issues with it I would suggest resetting the router to factory defaults, do not restore a backup, configure it manually and see if it works. If not, you probably have a hardware failure. For the USB modem part, no idea, never used it and Merlin himself doesn't touch that part of the firmware.

 

[pauligrinder]

The clock going back is normal, unless it gets an internet connection to retrieve the current time it will always default to this time. These routers not have a real time clock circuit, they rely on internet time servers.

For the rest of your issues, I can only comment on the 5Ghz WiFi, if you have issues with it I would suggest resetting the router to factory defaults, do not restore a backup, configure it manually and see if it works. If not, you probably have a hardware failure. For the USB modem part, no idea, never used it and Merlin himself doesn't touch that part of the firmware.

Yeah, I figured the clock thing might be like that... I find it kinda strange though that it doesn't write its' time somewhere so it could be restored after a reboot to get it approximately right before getting the precise time from NTP - because if the time is wrong, all kinds of certificate related failures occur.

The 5G WiFi works most of the time, but sometimes when I reboot it just doesn't seem to come up.

Anyway, like I said, I tried turning the router of over night and will turn it back on once I get home, so I'll report back once I see whether that helped... I suspect it may have overheated or something. It's got plenty of air around it etc, but our living room tends to get really hot when the sun shines. Also, this is my second AC56U, the first one died of overheating (it was inside a cabinet together with some external harddrives though).

 

[L&LD]

Let's see if the extended power off of all network equipment (all related power plugs pulled from the wall, correct?) will work for you.

For the surge protected power strip; I do not think that is any kind of protection at all. A quality UPS is recommended for all main networked equipment (if not the whole computer network).

Most surge protected power strips are actually worse than a simple power cable with how effective they are can protect equipment from harmful voltage swings.

 

[pauligrinder]

Let's see if the extended power off of all network equipment (all related power plugs pulled from the wall, correct?) will work for you.

For the surge protected power strip; I do not think that is any kind of protection at all. A quality UPS is recommended for all main networked equipment (if not the whole computer network).

Most surge protected power strips are actually worse than a simple power cable with how effective they are can protect equipment from harmful voltage swings.

Yeah, let's hope that helps, I'll be home in an hour or so and then we'll see.

Anyway, I don't think there's been any surge, and usually it's the ac-dc adapter rather than the actual device that blows if that happens (unless the surge comes through the phone line). I've had to replace dozens of D-link adapters after lightning storms, but only one actual router has broken, and that was when I forgot to unplug the phone line. That also broke the network chip of my original xbox in the process

Also this seems more like a software bug than a hardware failure to me, but yeah, we'll see ...

 

[L&LD]

After you upgraded to 380.59 did you follow this?

http://www.snbforums.com/threads/no...l-and-manual-configuration.27115/#post-205573


If after leaving the network down overnight it is still acting the same, the above is your next step to get your router to a known state and see if it is unstable because of software glitches.

 

[pauligrinder]

After you upgraded to 380.59 did you follow this?

http://www.snbforums.com/threads/no...l-and-manual-configuration.27115/#post-205573


If after leaving the network down overnight it is still acting the same, the above is your next step to get your router to a known state and see if it is unstable because of software glitches.

Nope, I haven't had to do anything like that after any upgrades so I thought I'd be fine this time too. The connection problems started before I upgraded though. But yeah, I'll follow the guide if the downtime didn't help.

 

[pauligrinder]

Yep, it didn't help

Now the router managed to update its' time using ntp and setup ddns though (after many failed attempts, according to the log), but still no internet. So, I guess it's time to follow the guide.

 

[pauligrinder]

I don't know wtf happened, but today everything started working again, without me doing anything... Mystical stuff