RTN66U Losing internet - always solved by pulling cable??

[Morph]

I've used Merlin on my RTN66U for a few years and recently updated to 380.68_4. That may be unrelated. My setup is, ASUS router connected to COMCAST modem.

Now, once a day, but not at the same time, it loses internet connectivity. I have swapped the port used on the comcast modem. No change - once that day, same thing.

I pulled the ethernet from the ASUS, waited a few seconds and put it back in, and it detects OK and comes back up. Internet restored! Does that mean its the actual port on the ASUS or, what? The cable modem is about 3 years old, and I can connect to its xfinity wifi fine, and direct to the ports on the back.

I have the syslog here: (it wont let me post it - keeps saying I am blocked if I try to paste in the 14KB text) ...

https://www.dropbox.com/s/ojqnwrsqpjmk79w/syslog.txt?dl=0

 

[kryptto]

Sorry reading this from my phone. I used to have Comcast and I will here provide my ways of fixing network issues.

First you are not describing or I am missing if you did wireless dropping or internet dropping. When having inconsistent wireless dropping, reset. Take the defaults and without modifying or customizing your wireless settings see if they majically get fixed.

If Comcast is dropping, hook your laptop/pc to the modem direct. Get a free uptime tool like https://www.manageengine.com/free-ping-tool/download.html

If it's Comcast have them test your line or demand a lineman to come out. That's the best I can offer at this time.

 

[Morph]

Thanks for the quick response. Its not the wifi that is the issue, its the lack of internet connectivity from the router outwards. I can login to the ASUS but any attempt to ping fails. Pulling the cable triggers a restart of the WAN interface on the ASUS and that fixes it.

I had a look at some of the scripts in https://www.snbforums.com/threads/your-isps-dhcp-does-not-function-properly.40947/page-2 but they seemed to cause my ISP connection to fail to come up after reboot - I didn't look much more into that but am familiar with scripting etc so willing to take on something like an autocheck restart script.

I have currently forced my ASUS WAN MAC clone to be the hardware WAN MAC of the router - I figured there was a chance that upon renewal by my ISP, the ASUS was sending a different MAC than when it started, so the ISP (modem) would basically reject that and break the link. Will let you know in about 24 hours.... If anyone thinks there is something else I should be doing, please shout.

 

[Morph]

Well, less than 24 hours. It did the same thing, so not the WAN MAC issue.

 

[Morph]

Some updates - can someone tell me what this points to as the problem?

I set a script to watch the WAN internet connectivity (via ping of 8.8.8.8) and when it failed the ping I issued a "service restart_wan". This caught the down event and restored it perfectly, without me needing to pull a cable. The syslog around that time was nothing special - no warnings etc. Here's the syslog after it does the wan restart (I removed my IP):

https://www.dropbox.com/s/17nlys1ld8mh2di/syslog-nov15.txt?dl=0

 

[redhat27]

I would recommend that you start with a factory reset of the router and check first, like @kryptto suggested. Let us know if the problem persists after a reset.

 

[ScubaCat]

I'd first simply power if off for a couple of minutes and then power it back on. Are there any errors in the log on the comcast modem? You didn't specify which device you have but for many (Arris) it's at http://192.168.100.1/

EDIT: I noticed pptpd running in your logs. Are you using PPTP to authenticate with Comcast? If not, and if it's disabled in the GUI, definitely go for the factory reset as something's not aligned with your config.

 

[Morph]

Thank you for the replies. I have gone ahead with the factory reset. WRT PPTPD, no that is just a server I have enabled for remote connections to the ASUS. The COMCAST device is a Technicolor TC8305C. There is just the ASUS plugged into LAN1 on the back. The cable used is a Cat5e (label on the side). I can see the IP lease for me from COMCAST is 4 days, so its not happening due to a DHCP renew. Anyway... it happens daily so I should know within 24 hours.

 

[Morph]

Well, that still failed and the internet was not accessible until I restarted the wan interface. Well, my script detected it and did it, which seemed to restore access. That was less than 6 hours between a complete factory reset, reboot and it failing. Suggestions welcome. syslog attached:

https://www.dropbox.com/s/mkj4480klrb9yrc/syslog-nov16.txt?dl=0

 

[redhat27]

Is your cable modem DOCSIS 2.0 or 3.0?
Comcast does not support 2.0 anymore.

Try to get comcast run a diagnostic check on your cable modem...

Also, why this:

Nov 16 09:36:32 dnsmasq[840]: using nameserver 75.75.76.76#53 for domain hsd1.fl.comcast.net
Nov 16 09:36:32 dnsmasq[840]: using nameserver 75.75.75.75#53 for domain hsd1.fl.comcast.net

then

Nov 16 09:38:53 dnsmasq[1139]: using nameserver 64.145.73.5#53
Nov 16 09:38:53 dnsmasq[1139]: using nameserver 209.107.219.5#53

 

[Morph]

Thank you again for responding so quickly.

The modem is comcast supplied so should be 3.0 compliant. Otherwise it wouldn't sync in the first place? If i connect my laptop direct to the modem there is no drop for more than 24 hours. Its not the modem as far as I can tell.

The dns change is because when it factory reset it defaulted to dns from comcast. I use a smartdns proxy and reconfigured the dns to be for those servers. I've been doing that also for years. When the fault occurs you cannot reach regular ip addresses... my check scripts uses 8.8.8.8 for example, as its target.

 

[Morph]

Still suffering. But some updates if anyone has comments:

I noticed that when my devices lost internet connectivity for new outbound attempts at websites etc (including when I logged into the router, I could not ping 8.8.8.8) ... a device which had an existing stream being sent to it over UDP (netflix, ROKU etc) *continued to work*! If I stopped the programme on the ROKU and tried to start again, it would fail like all the other devices.

I can fix the situation by restarting the WAN as before (services restart_wan) or through the WEB UI with turn off internet and turn it back on again (under Internet Status). I can also continue to access the internet if I switch to the xinfinity" wifi AP in the COMCAST modem, so the basic net route is still OK, it's just something has gone wrong with the WAN on the router.

I am still confused what could be the reason... maybe hardware failure? so I have bought a new N66U (as this model works well for me usually, on all counts). Looking at the "successors" form ASUS I am not sure I need all the extras. Is the N66U going to continue to be supported by Merlin firmware? The new models seem to support AC wifi (I don't need), run hotter in some cases ...

 

[owlyn]

I've used Merlin on my RTN66U for a few years and recently updated to 380.68_4. That may be unrelated. My setup is, ASUS router connected to COMCAST modem.

Now, once a day, but not at the same time, it loses internet connectivity. I have swapped the port used on the comcast modem. No change - once that day, same thing.

I pulled the ethernet from the ASUS, waited a few seconds and put it back in, and it detects OK and comes back up. Internet restored! Does that mean its the actual port on the ASUS or, what? The cable modem is about 3 years old, and I can connect to its xfinity wifi fine, and direct to the ports on the back.

I have the syslog here: (it wont let me post it - keeps saying I am blocked if I try to paste in the 14KB text) ...

https://www.dropbox.com/s/ojqnwrsqpjmk79w/syslog.txt?dl=0

This could possibly be a modem issue on the Ethernet side, and resetting the router resets that connection. I keep thinking I read something about problems with the TC modems, so you may want to also post in the Comcast Xfinity forum on DSLReports: https://www.dslreports.com/forum/comcast

 

[Morph]

Thanks for your response. I had a quick look through the forum and googled too, but don't see what you are referring to. Is there a recommended, inexpensive modem I could just buy to replace the COMCAST one I rent? I only need it to bridge to the ASUS as that has the features I want. Or... is there a newer COMCAST modem I should ask for?

EDIT: I just read https://20somethingfinance.com/how-to-replace-a-comcast-modem-with-your-own/ and can see what to replace it with. I'll try that as well, and hopefully one of these options will work.

 

[owlyn]

Thanks for your response. I had a quick look through the forum and googled too, but don't see what you are referring to. Is there a recommended, inexpensive modem I could just buy to replace the COMCAST one I rent? I only need it to bridge to the ASUS as that has the features I want. Or... is there a newer COMCAST modem I should ask for?

You are in luck. A new DOCSIS 3.0 modem eMTA (note- it is not a modem/router) that supports Comcast phone service was just released. It is the Netgear CM500V. I think it retails for $119. It is the modem I use and is very reliable. Downside is it is DOCSIS 3.0, not 3.1, and it does not support a built-in battery backup. Neither of these were anything I cared about. It is the only non-gateway, eMTA modem that can be purchased for use on Comcast. Payback period is 1 year vs. rental. Available through Amazon, and I think Best Buy. Maybe other places.

 

[Morph]

Thanks for that - the list from COMCAST is pretty long! I use a third party SIP provider for my voice (callcentric), so I had another look through the lists as I probably will never use the Voice service from COMCAST. I ended up choosing the ARRIS SURFboard SB6190 (https://www.amazon.com/gp/product/B016PE1X5K/?tag=snbforums-20) - if that works with the old N66U I will just hang onto them both. I'll still try the new 66U with the old modem (to see if the original 66U has some weird WAN fault), but it's probably time I shifted away from the "rented" modem anyway.

Will let you all know in a few days.

 

[ColinTaylor]

Is the N66U going to continue to be supported by Merlin firmware?

Probably not. See "Model support" in this post.

 

[Morph]

Thanks for that - I looked at the AC68U and 86U, but right now, there are quite a few poor reviews and the cost differential is pretty high for what I need. I appreciate everyone has different experiences, but for me, the N66U has been without any problems for nearly three years. I'd be happy to stick with a static FW if I could get a further 3 years out of the next one.

 

[bbunge]

Thanks for that - I looked at the AC68U and 86U, but right now, there are quite a few poor reviews and the cost differential is pretty high for what I need. I appreciate everyone has different experiences, but for me, the N66U has been without any problems for nearly three years. I'd be happy to stick with a static FW if I could get a further 3 years out of the next one.

Try a RT-AC66U B1. I replaced my N66R with one and am pleased with the features and performance!

Sent from my P01M using Tapatalk

 

[owlyn]

Thanks for that - the list from COMCAST is pretty long! I use a third party SIP provider for my voice (callcentric), so I had another look through the lists as I probably will never use the Voice service from COMCAST. I ended up choosing the ARRIS SURFboard SB6190 (https://www.amazon.com/gp/product/B016PE1X5K/?tag=snbforums-20) - if that works with the old N66U I will just hang onto them both. I'll still try the new 66U with the old modem (to see if the original 66U has some weird WAN fault), but it's probably time I shifted away from the "rented" modem anyway.

Will let you all know in a few days.

Note that if you subscribe to triple play, you MUST use an eMTA even if you don't actually use the phone service.