WiFi DNS Drops

shiver

shiver

shiver

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Joined
13 Jun 2007
Posts
1,378
Location
London
I have an interesting WiFi issue which admittedly I haven’t had much time to try and solve yet but I am wondering if anyone has had a similar experience.

I have noticed what seems like DNS timeouts or dropouts intermittently when using mobile devices (primarily iOS) when connected to WiFi on one side of my apartment. This can quickly be resolved by toggling WiFi off and on again. I assume it is DNS related as I have been able to use internal services during these times.

To hopefully give the full picture, my setup is as follows:

VM SH3 in Modem Mode —> Asus RT-AC68U —> Asus EA-AC87 AP where “—>” represents wired ethernet connections

[Asus RT-AC68U] -
  • Provides DHCP to all devices with multiple reserved devices (including the Asus EA-AC87 AP)
  • Raspberry Pi running Pi-hole connected directly to ethernet and powered by USB port
  • Multiple devices on ethernet, all without issues
  • 5GHz broadcast for WiFi devices (on this side of the apartment, DNS timeout does not occur

[Asus EA-AC87 AP] -
  • Running in AP mode
  • Same 5GHz SSID / auth as the Asus RT-AC68U but slightly different channel
  • Multiple devices on ethernet, all without issues
  • WiFi devices connect fine but drop DNS after a seemingly random amount of time.

Side note -

The Asus EA-AC87 AP replaced an ageing Apple AirPort Extreme (non-AC version) which whilst connect Wifi devices didn’t get the DNS issue, it has signal strength issues in the kitchen and was non-AC.

Any ideas?

Thanks in advance!


PS. *in before people say something about Ubiquiti UniFi instead* I have strongly considered it many times but resorted to buying the Asus AP as it was on a deal.
 
Ensure your Pi Hole is reachable via IP.
Ensure the router is handing the Pi-Hole IP off as DNS server.
What upstream DNS is your PiHole using? Ensure it is NOT Virgin's, try Google's for testing.
What DNS is your router using? Maybe that is picking up Virgin DNS and handing that off via DHCP? Ensure router is set to 8.8.8.8.
 
Thanks @Steveocee

Ensure your Pi Hole is reachable via IP. - Confirmed
Ensure the router is handing the Pi-Hole IP off as DNS server. - Confirmed
What upstream DNS is your PiHole using? Ensure it is NOT Virgin's, try Google's for testing. - It is 8.8.8.8 / 8.8.4.4 as default
What DNS is your router using? Maybe that is picking up Virgin DNS and handing that off via DHCP? Ensure router is set to 8.8.8.8. Router is set to use the Pi-Hole IP as DNS only, the same for the AP
 
What if you manually force the DNS on the wireless device when on the AP? Re-reading your OP, there is an assumption it is DNS based and whilst I'm not in any way contradicting this, what happens if you force DNS on the devices to 8.8.8.8? Do you still get the same issue?

Have you tested the cable between router and AP?
 
shiver said:
I have an interesting WiFi issue which admittedly I haven’t had much time to try and solve yet but I am wondering if anyone has had a similar experience.
Click to expand...

Have you tried setting your wifi to a different channel? It may be that your neighbour on that side is using the same wifi channel.
 
Steveocee said:
What if you manually force the DNS on the wireless device when on the AP? Re-reading your OP, there is an assumption it is DNS based and whilst I'm not in any way contradicting this, what happens if you force DNS on the devices to 8.8.8.8? Do you still get the same issue?

Have you tested the cable between router and AP?
Click to expand...

Going to try forcing DNS on devices this eve. And yes cable is working fine as far as the TV / Mac mini / Apple TV on the other end have been running
 
Quartz said:
Have you tried setting your wifi to a different channel? It may be that your neighbour on that side is using the same wifi channel.
Click to expand...

Yes that was my initial thought, I have tweak the channel to ~60 I think. Most other networks in the area are between 36-50 odd (EE and VM boxes).
 
shiver said:
Yes that was my initial thought, I have tweak the channel to ~60 I think. Most other networks in the area are between 36-50 odd (EE and VM boxes).
Click to expand...

Make sure you understand the channel numbers before you randomly pluck at them. Whilst fine to use, channel 60 requires use of a DFS wait period and constant monitoring so once you set it there is a chance it won't start broadcasting straight away and will complete a DFS wait/listen period which will only make you think there is a much larger problem in hand.

What channel width are you using? If not already, try bringing it down to 20mhz which will increase the spectral density and can often be an easy failsafe when having issues like this. Worry about ramping it up as and when you need to. Also staying to slimmer channels reduces the amount of co-channel interference which will be helpful if there are others around you.
 
Haven't had the enthusiam to tweak more this week due to work but will try over the weekend.

@Steveocee : currently at 80MHz (defaulted) so will try bringing it down, thanks.

@Quartz : 2.4GHz is off, all devices are on 5GHz
 
Small update - after a few attempts to tweak it, the issues persisted so I have ended up returning the Asus EA-AC87 AP.

My old AirPort Extreme is back in place, and I do not see the issue (but back to having a deadspot in the kitchen as before though).

I think I'll be eventually taking the plunge in some Ubiquiti kit when I get round to it. Thanks @Steveocee and @Quartz for the suggestions
 
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