The AC68 (AP only) does interrupt internet when rebooted....

[scheuri]

Hello all

This is kinda driving me insane here and I have nowhere else to turn...maybe you can shed some light here.

I owned an AC66U (192.168.x.2) used in AP mode only and an AC68U (192.168.x.1) as my default router connected to the ISPs modem. The AC66U (AP mode) had the AC68U as gateway. They are both connected by cable!
It appeared to work fine for me.

I decomissioned the AC66U by buying an AC86U which replaced the AC68U as main router (the AC86U therefore now connected to ISP modem and being in router mode) and wanted to use the AC68U now as AP only.
Therefore I put the AC68U into AP mode and gave it the 192.168.x.2 and set up the new AC86U with 192.168.x.1.

Internet worked fine, all the WLAN worked fine...until the first merlin firmware update.
When I updated the AP only AC68U my internet stopped working for a few seconds. And came back about properly after about 30 to 60 seconds. That was somewhat unexpected.
When I updated the AC86U the internet connection naturally went down. That was expected.

I tested a little and indeed...when rebooting the AP only AC68U (or updating the firmware) the whole internet connection goes down. And I am talking about main computers, not mobile devices connected to the AC68U.

Why?
I can't for the live of me figure out why a reboot or firmware update of the AC68U (which is AP only, and no DHCP or anything) does interrupt the internet connection of those devices that are linked by cable into the network and are directly talking to AC86U as main router/gateway....

Do you have any idea how to troubleshoot this further?

best regards
scheuri

 

[Grisu]

At which time of AP reboot exactly will you loose connectivity?
I think when it starts up maybe DHCP still enabled or starting with default IP address or something similar, so corrupting your network till it really is in AP mode.

 

[scheuri]

Good question: I might need to setup a syslog for that so I can monitor the logs from "AP only" and cross check with my internet connectivity tests.
WRONG: According to the WebGUI it is around 9% of the reboot?
Edit: According to the WebGUI the internet goes out at approx. 51% and gets back at approx. 74% (I have no idea if that is useful).

DHCP:
In the "ap only" router there are no options for DHCP in webgui and there is no udhcp process running after reboot on the "ap only" router. So, if DHCP is interfering for some reason then it must be enabled and disabled again rather quickly during reboot.

I will try to setup a syslog and maybe I get more info from there....
Edit: Synology seems not to be the perfect option for that....I have to investigate

 

[scheuri]

Oooohhhh boy, was I wrong.

Not only the internet is down and disconnected, but also my whole internal network is down. Only by rebooting the Asus AC68U which is configured as "AP only". This kinda blows my mind.
I tried to syslog the data from the AC68 to my linux host, but naturally not everything is being recorded as the whole internal network is down as well...
Funny enough...when power off the AC68, my network still works fine...including internet. So, something is pretty much borked when that little thing reboots....

 

[PolarBear]

Oooohhhh boy, was I wrong.

Not only the internet is down and disconnected, but also my whole internal network is down. Only by rebooting the Asus AC68U which is configured as "AP only".

Could it be that when it reboots, it starts off with a default IP which is the same as your main router ?

A test might be to switch off the radios and then reboot. If the whole network still goes down, it must something to do with the interaction between the AP and the main router (or other devices attached to the main router).

I would suspect a an IP conflict between the AP and the main router itself, rather than between the AP and another device attached to the main router. (In the latter case, I would expect only the "other device" to experience problems).

(Edit: fixed typo to clarify)

I tried to syslog the data from the AC68 to my linux host, but naturally not everything is being recorded as the whole internal network is down as well...

Could you write the syslog to a USB stick plugged into the router ? The USB would probably work, even if the whole network were down.

 

[ColinTaylor]

Did you reload an old saved settings file from one of your older routers onto one of the new ones?

Have you tried doing a factory default reset and manual setup on your router and/or AP?