386.4 “Internet disconnected” after reboot modem

[Morac]

I have an RT-AC88U running 386.4. Today I rebooted my modem. When the modem booted up I briefly had Internet, but then lost it. I checked the router and it said the Internet was disconnected. I waited a bit and it didn’t change, so I toggled Internet off and on. That got the router to recognize that the Internet was up, but the DDNS registration hung and the router had no IPV6. I ended up rebooting the router and then everything worked normally.

I’ve rebooted my modem dozens of times before and never had to reboot the router to get things working. This is the first time I’ve done so under 386.4. Any idea why the router didn’t re-establish an Internet connection?

 

[Morac]

About 8 hours later I noticed a number of devices were having problems getting an IPv6 address. Rebooting would fix them temporarily, but they’d lose it after about 15 minutes. Some didn’t have that issue, but most did.

I powered off the router and back on about an hour ago and that seemed to resolve the issues so far.

 

[DJones]

About 8 hours later I noticed a number of devices were having problems getting an IPv6 address. Rebooting would fix them temporarily, but they’d lose it after about 15 minutes. Some didn’t have that issue, but most did.

I powered off the router and back on about an hour ago and that seemed to resolve the issues so far.

If you don’t require ipv6 I’d disable it. IPv4 is sufficient in most cases and has less problems especially on the latest firmware of Merlin.

 

[Morac]

If you don’t require ipv6 I’d disable it. IPv4 is sufficient in most cases and has less problems especially on the latest firmware of Merlin.

IPv6 tends to be faster.

Also for some reason if my Android TV doesn’t use IPv6 it resets its network every 1 to 10 minutes which causes it to open a bunch of network connections which can eventually lock up my router depending on how many it does.

I’ve found IPv6 to normally be reliable except in this case. Also the WAN detection didn’t work (I don’t block any outbound connections).

 

[DJones]

IPv6 tends to be faster.

Also for some reason if my Android TV doesn’t use IPv6 it resets its network every 1 to 10 minutes which causes it to open a bunch of network connections which can eventually lock up my router depending on how many it does.

I’ve found IPv6 to normally be reliable except in this case. Also the WAN detection didn’t work (I don’t block any outbound connections).

No idea why your android tv is doing that. IPv6 doesn’t need NAT so maybe that’s why it’s playing nicer? Upnp with secure mode on might help for ipv4. Idk.

If wan monitoring issues persists even after the use of the command by Merlin below check your logs if it’s preventing rebinds at dns.msftncsi.com if so then allow rebinds.


Add this line to /jffs/configs/dnsmasq.conf.add if you're running Merlin:
Code:
rebind-domain-ok=dns.msftncsi.com



NEW: IPv6 support for OpenVPN server. Allows to remotely
connect to your router's OpenVPN server over IPv6, and
reach LAN clients over their IPv6 (redirecting IPv6
Internet traffic does not work).

Known issues:

• Internet reported as disconnected
  Your Internet monitoring configuration is most likely incorrect. Reset it to its default settings by running these over SSH:
  
  Code:
  nvram set dns_probe_content="131.107.255.255 112.4.20.71 fd3e:4f5a:5b81::1"
  nvram set dns_probe_host="dns.msftncsi.com"
  nvram commit

Release - Asuswrt-Merlin 386.4 is now available

After a long wait, the new version of Asuswrt-Merlin is now available. 386.4 merges with GPL 386_45958 (plus a number of security fixes backported from newer code), updates various components, and also adds support for the RT-AX86S (uses the same firmware as the RT-AX86U). The highlights of...

www.snbforums.com

 

[heysoundude]

About 8 hours later I noticed a number of devices were having problems getting an IPv6 address. Rebooting would fix them temporarily, but they’d lose it after about 15 minutes. Some didn’t have that issue, but most did.

I powered off the router and back on about an hour ago and that seemed to resolve the issues so far.

I've found for a while now that if I have to reboot my AC86, I also need to reboot my ISP's bridged modem or things don't quite work right on my network.

If you don’t require ipv6 I’d disable it. IPv4 is sufficient in most cases and has less problems especially on the latest firmware of Merlin.

it's 2022, and IPv6 has been around for 20 (?) years. but IPv4 may only be in use another 20. it can't hurt to possibly get a bit ahead of the curve and start learning it now. Everybody's doin' it, man: Google/Alphabet, Amazon/AWS, Reddit, SmallNetBuilder/Forums ;-)
And as far as the differences in functioning of the android box mentioned, Android is a google product and just about everything google is VERY good with IPv6. The Merlin issue (or does it affect Asus running stock FW too?) will be resolved soon enough...

 

[DJones]

I've found for a while now that if I have to reboot my AC86, I also need to reboot my ISP's bridged modem or things don't quite work right on my network.

it's 2022, and IPv6 has been around for 20 (?) years. but IPv4 may only be in use another 20. it can't hurt to possibly get a bit ahead of the curve and start learning it now. Everybody's doin' it, man: Google/Alphabet, Amazon/AWS, Reddit, SmallNetBuilder/Forums ;-)
And as far as the differences in functioning of the android box mentioned, Android is a google product and just about everything google is VERY good with IPv6. The Merlin issue (or does it affect Asus running stock FW too?) will be resolved soon enough...

Drafted in 1998, but ipv6 launched in 2012 so 9 years. But anyways I said disable it because my thoughts are if he can’t stay online with ipv6 and ipv4 works then that’s more important short term. Obviously if he needs it or wants it then he’s going to have to troubleshoot the issue more. Nothing wrong with ipv6 it’s the long term solution for the issue of IP address depletion among other things.

Might be google but ipv4 is the de facto standard if they can’t make a stable product that works with the internet then it’s trash software. But more likely it’s a setting or setup issue that makes it not like ipv4.

Firmware and wan detection issues will get fixed but in case all else fails…. Least he’s in the right place to ask for help.

 

[Morac]

If wan monitoring issues persists even after the use of the command by Merlin below check your logs if it’s preventing rebinds at dns.msftncsi.com if so then allow rebinds.


Add this line to /jffs/configs/dnsmasq.conf.add if you're running Merlin:
Code:
rebind-domain-ok=dns.msftncsi.com

WAN monitoring seems to work as I haven't had an issue for 24 days and in this case the WAN did go down as I rebooted my modem. The problem is that it didn't detect the WAN was back up. I think part of the problem may be that after the modem reboots, but before it signal locks, it feeds the router a private IP address via DHCP. Once the modem locks, it will feed the actual public IPV4 address via DHCP and shortly afterwards any IPV6 addresses.

I'm not sure how the WAN detection code works, but it won't be able to get to dns.msftncsi.com with the private IP address. It needs to grab the public one to do that.

Previously the router would get the private IP address and then somehow detect the change and pick up the public address about 5 to 10 seconds later. Now it doesn't. Fortunately my modem doesn't do that if the Internet goes down temporarily, unless that triggers a reboot.

 

[DJones]

WAN monitoring seems to work as I haven't had an issue for 24 days and in this case the WAN did go down as I rebooted my modem. The problem is that it didn't detect the WAN was back up. I think part of the problem may be that after the modem reboots, but before it signal locks, it feeds the router a private IP address via DHCP. Once the modem locks, it will feed the actual public IPV4 address via DHCP and shortly afterwards any IPV6 addresses.

I'm not sure how the WAN detection code works, but it won't be able to get to dns.msftncsi.com with the private IP address. It needs to grab the public one to do that.

Previously the router would get the private IP address and then somehow detect the change and pick up the public address about 5 to 10 seconds later. Now it doesn't. Fortunately my modem doesn't do that if the Internet goes down temporarily, unless that triggers a reboot.

In the case of say dsl you have 2 options dns probe or ppp echo under WAN setting. I’m not sure how it detects if you run automatic ip for wan. Maybe verify you have the correct drop down option selected. And check under administration system you have detection setup correctly.

Only a real issue if it keeps persisting though.

 

[heysoundude]

Obviously if he needs it or wants it then he’s going to have to troubleshoot the issue more. Nothing wrong with ipv6 it’s the long term solution for the issue of IP address depletion among other things.

Might be google but ipv4 is the de facto standard if they can’t make a stable product that works with the internet then it’s trash software. But more likely it’s a setting or setup issue that makes it not like ipv4.

Firmware and wan detection issues will get fixed but in case all else fails…. Least he’s in the right place to ask for help.

v6 might be the default starting point, which might be able to be disabled if it's an issue, but I doubt that's it...other HW/config issues are most likely.
(I'm of the opinion there's no standard, de facto or otherwise right at the moment - it seems to be up to users/admins, and it seems to me they're leaning increasingly towards v6 for whatever reason)
and by my math, v6 is in it's 23rd/24th year (depending on whether you consider life to be from conception or not? lol)...invented/created a quarter century ago basically. ancient by modern tech standards, right?

 

[Morac]

Well my Internet went down today for about 5 minutes when my modem went offline. The router detected It was down and it detected when it came back up.

I’m not sure why it had a problem yesterday when I rebooted it. Like I mentioned I think the main difference is rebooting the modem causes it to assign a private IP address at first.

On a side note, I have cable, not dsl and I don’t have ping or dns query enabled for network monitoring. It looks like if neither is checked, ntp is used which should work.

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