Dual WAN with only one internet connection!?

[ceglia]

(edited: changed Verizon FiOS to AT&T Fiber)

I have two GT-AX11000 routers, one set up as the main router and the other as a wired Access Point.  Ever since switching from Spectrum to Verizion FiOS AT&T Fiber for internet services, my main router will periodically lose internet connection (every 5 days or so) rendering every network device that relies on internet (wired or wireless) unusable.  The only solution seems to be to reboot the main router.  Then everything goes back to normal.

As a partial solution, I enabled the Reboot Scheduler on both routers so that they reboot every night at 4am.  This helps but does not completely eliminate the problem.  My internet now drops out every 15 days or so.

My theory is that the FiOS AT&T modem is to blame, but I'm not 100% sure.  It's a modem/router combo, and to get it to work with my GT-AX11000, I have to set the FiOS AT&T modem to "passthrough" (the Spectrum modem/router had more features and I could set it to "bridge" mode which worked flawlessly).  But every so often, it disconnects my GT-AX11000 and everything downstream.  My internet works just fine up to the FiOS AT&T device, but somehow my GT-AX11000 loses its connection.

Anyway, last night I tried a new solution that I'm hoping will work.  I enabled Dual WAN on my main GT-AX11000 router and ran a SECOND ethernet cable from my FiOS AT&T router to one of the LAN ports of my main GT-AX11000 router.  In other words, my main GT-AX11000 router is connected to the FiOS AT&T modem TWICE: once via the WAN port and once via LAN 1.

I set the Dual WAN mode to "Fail Over" and enabled "failback".  I then set my Auto Network Detection settings to 5 seconds, 12 attempts (4 attempts for failback), and set Network Monitoring to DNS Query.

I did a quick test to see if the setup would work by unplugging the Primary WAN ethernet cable from the back of the FiOS AT&T modem, and sure enough after 60 seconds, my router switched over to the Secondary WAN connection (which is also connected to the FiOS AT&T modem).  Everything was working great.

I then plugged the Primary WAN ethernet cable back into the FiOS AT&T modem, and soon afterwards, my router switched back over to the Primary WAN connection.

Amazing, right?  Well.... maybe.  I still have to see if this will work under real world conditions, but I'm hopeful this workaround will keep my disconnections to a minimum.  If this works as I hope it does, in theory I would only be disconnected for a maximum of 60 seconds and everything would reconnect automatically.  My routers will still automatically reboot each night at 4am, just to reset all connections.

It's very possible though that when my Primary WAN loses its connection under real world conditions, the Secondary WAN connection will also drop.  Anyway.... fingers crossed.

Has anyone else tried connecting their router to the same modem twice and enabled WAN??

[ceglia]

Ok, quick update.  some good news, and some bad news.

first the good news. enabling dual WAN in "Fail Over" mode mostly works, and it appears i can rely on it temporarily if the internet connection drops. whenever the primary connection loses internet, the secondary connection (which is just the same router connected to the same gateway using a second ethernet cable) kicks in and works with almost all of my devices. the only device that does not appear to reconnect is my iphone. but it only refuses to reconnect to my main GT-AX11000 router. it WILL reconnect to my second AP GT-AX11000 router. and if it's out of range of my second router, it switches to LTE. very weird behavior, but in essence, I'm fine.

i still have my reboot scheduled every day at 4am, and when that reboot occurs, my connection switches back to the primary connection and then everything is restored to normal, including my cell phone.

the bad news is that i'm still losing my internet connection regularly, and i'd really like to understand why.  i'm going to try monitoring my logs to see if i can find some clues, but there's a ton of crap in there, and i suspect it's going to be hard to pinpoint the issue.  anyway.... we shall see.

[Saltgrass]

When you refer to your iPhone connecting or disconnecting, you are referring to the wireless to the router?  You are not referring to having it set as the second WAN, which is possible now on the AXE16000? 

I don't remember, but you have contacted your ISP and allowed them to check your install?  I know they can see what is going on with your connection.

I am still having a problem with your Dual WAN configuration.   All I might think is the delay switching from primary to secondary gives the system time to reconnect, but then the primary WAN would take back control once it was re-established.  I don't suppose there were any type of time variables as to how this process happens?

[ceglia]

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@Saltgrass wrote:

When you refer to your iPhone connecting or disconnecting, you are referring to the wireless to the router?  You are not referring to having it set as the second WAN, which is possible now on the AXE16000? 

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When my primary connection goes down and my secondary connection kicks in, my iphone can no longer connect to the WiFi network via the primary GT-AX11000 router.  but it CAN connect to the WiFi network via the second AP mode GT-AX11000 router if it's close enough to it.  it's definitely odd, but in practice it doesn't make much difference since my cell phone can always connect to TMobile LTE (and in any case, I'm not doing any serious internet work on my phone other than casual browsing/email type stuff).  if/when that does happen, it's only for a few hours since my routers reboot at 4AM each day anyway.

definitely odd and definitely something i'd like to resolve at some point just because it shouldn't be happening, but in practice, it has no impact on anything.

i am NOT using my phone for the secondary WAN connection.  my secondary WAN connection is nothing more than a second ethernet cable running my main router to the same AT&T gateway.  it's obviously not how dual WAN was intended to work, but interestingly in my case it does work, and until i find the root cause of my problems, it helps me address my frequent disconnects -- especially when i'm not at home to manually reboot my routers.

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@Saltgrass wrote:

I don't remember, but you have contacted your ISP and allowed them to check your install?  I know they can see what is going on with your connection.

honestly, whenever i call AT&T, they're pretty clueless and offer virtually no support for problems that involve third party equipment.  at best, they will direct you to this page: https://www.att.com/support/smallbusiness/article/smb-internet/KM1188700?_gl=1*11i2qoy*_gcl_au*NTc3N.... at worst, they'll have you run a series of pointless tests that involve bypassing the Asus router altogether.  and of course, the problem then goes away, and so they refuse to help blaming the Asus router.

i've done quite a bit of research into the AT&T side of things, and for the time being, i've ruled out the gateway as the source of my problems.  it's configured per AT&T specs to work with third party routers, it matches every forum post i've ever read by independent users using third party routers with this gateway, and it's super stable.  it has never once in the last 12 months dropped its connection.  it's the first thing i check.  the gateway is always connected.  it's the Asus router that loses its connection to the gateway for some reason.

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@Saltgrass wrote:

I am still having a problem with your Dual WAN configuration.   All I might think is the delay switching from primary to secondary gives the system time to reconnect, but then the primary WAN would take back control once it was re-established.  I don't suppose there were any type of time variables as to how this process happens?

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I'm not sure i understand your question.  When in "Fail Over" mode, if the primary connection goes down, the Auto Network Detection procedure kicks in.  Every 5 seconds it runs a DNS query to see if it can reestablish a connection to the internet.  if that query fails 12 consecutive times, it activates the secondary connection.  But it also continues checking the primary connection in case it comes back.  if it successfully queries the primary connection 4 consecutive times (with 5 second intervals), it switches back from secondary to primary.  This is called the "Failback Trigger".

in my case, the primary will go down and never come back until the router is either manually rebooted by me or automatically rebooted at 4am by my reboot scheduler.  and that's not because the "Failback Trigger" is defective. it's because the primary connection to the gaterway is never restored on its own.  it needs a reboot.  i know this because i tested the system early on when i first looked into dual WAN as a possible solution, and the "Failback Trigger" works great if the connection is actually restored.

i think the answer lies in the logs, but this happens somewhat infrequently, so i need to wait until the next failure to see what i can find.  i also have some hope in the MAC address cloning idea. we shall see.  for the time being, everything essentially works even though it's held together by duct tape and chewing gum. 😂 

[Saltgrass]

I found a site that discusses what you just mentioned.  It also talks about how the router checks for a connection.  

This might give you an advantage in the log if you can change or see where the router is checking the connection, it might be easier to find.  If you set it to use something like google, you might be able to see that easily in the logs.

Right now, my router (AXE16000) appears to be set to check every 3 seconds and if it fails twice, it jumps to the alternate.

[ceglia]

Important Update: I am NO LONGER using this strange Dual WAN workaround.  While it did allow me to maintain an internet connection whenever the primary connection failed, I discovered that the secondary connection appeared to bypass my router altogether.  And I suspect this was leaving all or most of my devices exposed and unprotected behind the router's firewall.

I noticed this when I logged into my AT&T Gateway.  With Dual WAN disabled, I can only see my router from the Gateway's admin page, everything behind the router is hidden and protected, as it should be.  This is important because the Gateway is set to passthrough mode with its firewall disabled.  The router's firewall is what protects all of my devices.

With Dual WAN enabled and a second ethernet cable connecting my router to the same Gateway, I was suddenly able to see every device that was connected to my router.  It was as if a pathway had been opened bypassing my router's firewall.  I'm assuming my devices were unprotected in this configuration.  So... ignore this whole workaround.  It works, but the risks outweigh the benefits.