DNS Services using 466 of the 515 MB used so far... why??

[rgomez]

Hello,

I just noticed on my carrier's app that my usage was way up for the usual in me. It's been 3 days since the last reset and I have already consumed around 512Mb of the 4Gb I have available. In a normal month I usually use maybe 1Gb or 2 *at most*, so in 3 days having used 512Mb is just a lot.

So, I went to see the Cellular data page on te Settings app, and no app is using anything to be worried about. The culprit is inside System Services, and it is DNS services.

This doesn't make sense at all to me. I'm usually on a WiFi network, and for what the carrier's App say, the big jump was today: it says that I have used 472Mb today, versus 12-15Mb the days before. Today I have been maybe for 80 minutes without WiFi (the car to the office, and later walking the dog) and I only hear music on that times, very seldom use anything else by myself.

So, what could be the reason for a spike on DNS services today? Is there a way to track the app that made the original requests? I have checked the battery usage to see if there is some app that has used too much battery (I mean, 450Mb of DNS requests are *a lot* of requests!) but I can't see anything strange, everything feels normal: WhatsApp on background, Music on background, FB on background.

Does anybody knows if the DNS requests always go on the cellular network? I believe that the notifications always use the cellular network, but I wonder if the DNS too? In any case, I don't recall doing anything out of the ordinary today to justify so much requests.

I am worried because I'm going on a trip on a few weeks and definitely need to have my cellular data available...

It is an iPhone 6s with iOS 10.0.1 (was on the developer betas, but since the GM came out I installed it, so I have been on this version for a week or so)

 

[rgomez]

Here is a screenshot of the data usage.

I have been monitoring since I saw this and so far nothing has happened again, doing more or less the same I remember doing yesterday on the periods without wifi.

I also checked my GF's iPhone and she has maybe 1Mb of DNS requests for 18 months or so of usage: 29Gb (she has never touched that setting so the statistics are since she got the phone). I just don't understand how I got 466 on maybe 90 minutes. Doesn't make any sense.

I did reset my network settings yesterday after finding this. Hopefully that did the trick.

The data was in fact counted by my carrier, so this doesn't appear to be just a thing from my side: the traffic was in fact going by the cellular data.

 

[unglued]

That is strange because DNS queries are small in size. Try turning off Wi-Fi Assist in Settings > Cellular it's at the very bottom. I believe that setting is on by default, see if that helps cut usage.

 

[rgomez]

That is strange because DNS queries are small in size. Try turning off Wi-Fi Assist in Settings > Cellular it's at the very bottom. I believe that setting is on by default, see if that helps cut usage.

Yes, 466Mb of DNS queries would be something like 2^32 typical sized requests... which is suspiciously the max value for a 4 bytes unsigned integer... anyway, it's a lot of queries and I doubt several years of typical usage would produce that much requests.

I turned off the Wi-Fi Assist, but it only reported 515Kb of usage. In any case, I shouldn't need it so let's see.

So far things have been normal.

 

[unglued]

Maybe your carrier can provide a DNS log to see what's going on or they might be able to configure your phone to use a different DNS server if the problem continues.

Would be interesting if you could get a network analyzer or sniffer tool/app to capture traffic to/from your iPhone and filter out DNS, I've never tried it on an iOS device let alone over a cell connection. We use Wireshark at work but I don't think they have an iOS app.

 

[rgomez]

Maybe your carrier can provide a DNS log to see what's going on or they might be able to configure your phone to use a different DNS server if the problem continues.

Would be interesting if you could get a network analyzer or sniffer tool/app to capture traffic to/from your iPhone and filter out DNS, I've never tried it on an iOS device let alone over a cell connection. We use Wireshark at work but I don't think they have an iOS app.

I will ask them, but I really doubt they will be able (or want) to provide anything remotely useful.

I have been keeping an eye with an app called Net Analyzer and another (from the same company) called Status. But something more complex like a sniffer I don't really think could be possible for a cell connection.

I will check my office's firewall logs and see if there are too much DNS requests from my iPhone, but I doubt it, at least from what I can see on those apps, things have been behaving correctly since the reset of the network settings.

 

[unglued]

I will check my office's firewall logs and see if there are too much DNS requests from my iPhone, but I doubt it.

Wouldn't hurt to check but it would be more for Wifi/hardwired traffic. I'm guessing the Cellular > System Services > DNS Services log is for cell data only.

 

[rgomez]

Wouldn't hurt to check but it would be more for Wifi/hardwired traffic. I'm guessing the Cellular > System Services > DNS Services log is for cell data only.

Yes, I assume everything under the Cellular settings is just for the cellular traffic. I was thinking in comparing what my firewall reports for the WiFi connection, to see if it is in fact sending that much requests. but so far I don't see anything that could produce that much requests.
[doublepost=1474137367][/doublepost]So... I contacted Apple Support to mention this. And so far, the people attending me is telling me that the iPhone does not register that info. That it's the cellular provider the one that does. And she keeps just giving me stupid reasons and reasonings....
[doublepost=1474137487][/doublepost]Ok. She closed the chat session when I asked if she know what a DNS request was... not going to get any help there I see.

 

[unglued]

That's correct the cell/data traffic flows through the cellular provider's equipment/routers/servers, third-parties, etc. so they should have the answers. But like you said before it's doubtful to get anything remotely useful from these guys, ask to speak to their tech support, good luck!

 

[rgomez]

I still have to go to my carrier's offices and try to get this info... but in any case, there appears to be still a big number of DNS requests being made.

Since my first screenshot, I have another 20Mb of DNS requests made, for a total of 486Mb.

Is anyone seeing such an increased number of DNS requests with the iOS 10?

 

[elistan]

Definitely odd. My DNS Services usage for three years is only 24.6 MB. (I never reset my stats.)
And I've been on iOS 10 since it came out. This is on a 5S.

 

[geoff5093]

That's correct the cell/data traffic flows through the cellular provider's equipment/routers/servers, third-parties, etc. so they should have the answers. But like you said before it's doubtful to get anything remotely useful from these guys, ask to speak to their tech support, good luck!

Remember, tech support generally tell you to turn it off and on, factory reset, etc. They have little knowledge of somewhat technical questions, let alone asking for DNS logs. If you try to get to someone who knows what you're talking about, it would be a miracle.

 

[rgomez]

Well, some days later, after restoring it (!) and, yesterday, updating to 10.0.2, I reset the statistics. And yesterday, again, I got 13MB of DNS services for 20MB of total cellular usage. And I still can't figure out what's causing this.

I have deleted 2 of the last apps I installed (although I installed them weeks before this problem happening for the first time, and there haven't been updates) and I will check today if this happens again... but this is just blindly trying to fix something that I have no idea where or why is it happening.

 

[rgomez]

And yet again. It used 10MB today at some point while I was on the movies...

At least I know that the two apps that I uninstalled are not the culprits.

 

[rgomez]

Well, this keeps happening. I contacted AppleCare one week ago, and the woman who attended me was very responsive and apparently she did understand the problem. She was going to contact someone higher up, and then, in 24-48 hours, contact me.

1 week later, and 4 emails from my part to she, I haven't got any reply. What I did get was some 100MB or so of DNS traffic. I also think that the Location and Time services are using more than needed... but without help from Apple it's impossible for me to track down what application is using causing it, and I'm almost sure it's no App that can be disabled from the cellular data configuration (as I have had traffic even with all apps disabled there).

I am now on another country (Canada), with another carrier (Although using my mexican contract with AT&T, that includes roaming in USA and Canada) and it still happens. So it's not that the DNS server assigned by my carrier is returning corrupted records, as now I'm using another DNS altogether.