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rgomez Author

Level 1

22 points

DNS Services using way more data than before with iOS 10?

Hello,

I upgraded to iOS 10 since the GM became available.

Some days ago I noticed a spike in my data usage on my carrier's report, and I went to check on the iPhone what was causing this. To my surprise, the culprit was DNS Services. Of the 515Mb I had consumed since the last reset (I reset it the same day as my carrier, which was on Sept 13th) 466Mb were DNS Services.

On the carrier's app I see that on Sept 16th there were 490Mb consumed, vs an average of 15-20Mb per day. So I assume most of those 466Mb were made that day.

Now, 466Mb of DNS requests are something like 5 billion requests. I was without WiFi connectivity that day for a total of maybe 90 minutes. In that time I did not use the iPhone except to hear music (60 minutes walking the dog, another 30 on the car). I can't figure out how or what made those requests.

I reseted the Network settings that day, and things have gone back to "normal". Except that today I can see that there are another 20Mb of DNS requests being made since the 16th. 20Mb of DNS requests are still *a lot*.

Has anybody else noticed an increased amount of DNS requests with the iOS 10?

Now, the strange part is that everything was normal before the 16th. And I installed the GM the day it came out (which was... 1 week or so before?) and I was on the betas since weeks before. I can't remember or see anything different or special being made on the 16th. Some days before, IIRC, there were some carrier updates, but why or how that would produce such an increase in DNS requests?

I tried talking with Apple Support, but the girl whom I was talking with just told me incorrect and illogical stuff, and got offended when I asked if she knew what a DNS request was, and closed the chat session. I am guessing I wont get any help there.

iPhone 6s, iOS 10

Posted on Sep 19, 2016 10:12 AM

23 replies

rgomez Author

Level 1

22 points

Oct 2, 2016 6:23 PM in response to 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 at all. 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 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 (got 12MB today). So it's not that the DNS server assigned by my carrier is returning corrupted records, as now I'm using another DNS altogether.

I will try going to an Apple Store and see if the Genius bar has something to offer me, but as I don't think this is a hardware problem, I can only hope that they can check the logs of the iPhone directly and see what DNS requests are being made (that was my original intention with the call to AppleCare) and that could probably give an idea of where the problem is... but I don't know if they can in fact access those logs, or even if there are logs for the DNS requests being made at all.

moaggus

Level 1

8 points

Nov 12, 2016 4:45 AM in response to rgomez

I seem to have the exact same issue with my iPhone 7 and iOS 10.1.1: a few days after a clean factory reset, the DNS service produced 400 MByte of mobile data traffic within less than 3 days!
Does anyone have a workaround/fix for this yet, or at least a reply from Apple support?

Nov 12, 2016 7:04 AM in response to moaggus

moaggus wrote:

I seem to have the exact same issue with my iPhone 7 and iOS 10.1.1: a few days after a clean factory reset, the DNS service produced 400 MByte of mobile data traffic within less than 3 days!
Does anyone have a workaround/fix for this yet, or at least a reply from Apple support?

This is a user-to-user forum; Apple does not participate or respond here. If you want a reply from Apple support go to https://getsupport.apple.com.

moaggus

Level 1

8 points

Nov 12, 2016 7:14 AM in response to Lawrence Finch

Lawrence Finch wrote:

This is a user-to-user forum; Apple does not participate or respond here. If you want a reply from Apple support go to https://getsupport.apple.com.

Hi Lawrence, thanks for the info and yes I am fully aware of that. That's why I asked if any of the users already went through the process of contacting Apple and maybe received a result. If that is not the case, then I will of course contact Apple myself. But as Gualberto wrote over a month ago that he would post back results, I thought maybe he got a result but forgot to respond here.

The only workaround that I found out so far was that mobile network/WIFI support can be disabled in order to avoid data traffic from system services/general. But I guess this does not cover the issue with system services/DNA. However, I give it a try and post results here.

Nov 19, 2016 4:27 AM in response to rgomez

I was wondering if you have any updates, I have this is issue as well.

When I received my first iPhone 7, DNS services consumed 4.5 gigabytes while on wifi (wifi assist was off, has been off since the implemented the feature last year).

I put in a case with Apple's engineers and they notified me a week later saying they had an update but after repeated attempts I could never get them to reply back to me. I had contacted Verizon (my carrier) as well about the issue and they suggested replacing the iPhone.

I received my 2nd iPhone 7 from Verizon on Thursday, set it up as a new iPhone, downloaded the iOS updates, and began downloading my apps and files again on wifi. This is all with "wifi assist" off and "use cellular data" off for everything but Safari, email, and messaging. In less than 12 hours DNS services used 2.5 gigabytes.

Looking at my verizon account and the time stamps of the data usage it appears to have happened when my apps were downloading and then when Apple Music was downloading my library. Those are the times that seemed to trigger the heavy DNS usage on my previous iPhone 7 as well.

I put in a new case with Apple support last night and I will update if / when I hear back from them, but in the meantime, if anyone else has an update I would greatly appreciate it.

Thanks in advance.

Nov 23, 2016 10:07 AM in response to LRembrandt

Same issue. Lots of costs because of it :(

jfaughnan

Level 3

870 points

Jan 31, 2017 7:50 PM in response to LRembrandt

My daughter and I both have iPhone 6 and AT&T and iOS 10.latest.

My DNS use: 684kb

Her DNS use: 148MB

Not same period but her data use for DNS is crazy. Something is broken here.

jfaughnan

Level 3

870 points

Jul 2, 2017 7:10 PM in response to bizringer

This certainly sounds like a bug of some kind, but it might be a network provider bug. If you use an iOS content blocker like Purify.app does your DNS use drop?

DNS Services using way more data than before with iOS 10?