8 ms·

Why DNS in OS X 10.10 is broken, and what you can do to fix it

98 points by xvirk 12y ago

webscale2015 12y ago
Author is clearly holding it wrong, it just works, until it doesn't, then the user is still wrong.
rnhmjoj 12y ago
I had the "<hostname> is already in use" problem, the safari not able to resolve any hostname and I could not use wake on demand for almost 2 years because of some bug. Maybe I am unusually unlucky but I agree that the quality of the last OS X releases has clearly got worse. The problem with apple software is that if it doesn't "just work" there is little to do about it. I am not so sure about reenabling mDNSResponder. This may cause worse problems.
- webscale2015 12y ago
  Their software has improved on the mobile front, it seems that's where all their engineers focus these days. It is sad that mac users long for the stability, speed and simple effectiveness of previous versions.
  - rnhmjoj 12y ago
    Yes, probably OS X is a bit left aside nowadays.
  - protomyth 12y ago
    I wouldn't say that. We are still experiencing the iOS won't connect to wifi bug. The really chaotic thing is that iPhones or iPads of the exact same model and software revision (current iOS 8.1.3) will randomly connect, not connect, or connect long enough to get an ip address then not be able to do anything. It is really getting quite frustrating. We have a Cisco 5807 controller and the 3702e wireless points. Every other OS works just fine. Only having trouble with Apple products and randomly at that.
    - craigching 12y ago
      Agree, having wifi problems myself, pretty much have to restart it on every use and that seems to get me around it until the next time it sleeps. I'm at the point of considering going back to iOS 7 on all my devices.
      - protomyth 12y ago
        I'm just baffled because we have (among tens of other devices) two iPhones with the same model number and one works and one doesn't. I have some students very happy and some very unhappy. Its not like I can get logs from these folks to figure out what the difference is.
  - FireBeyond 12y ago
    You don't use third party keyboards, then? Because they regularly break. Swiftype, Swype. Keyboards disappear. All sorts of stuff. And iOS 8 isn't really that much better. I've seen weird screens where all the apps are shown, in different orientations, text rotated while the app maintains a different orientation, in Apple apps and third party.
feld 12y ago
I've seen the Safari hangs -- sometimes it won't even open a new (empty!) tab. I knew it had to be network related, but forgot that discoveryd is in 10.10 or I would have suspected DNS right away. edit: anyone remember how broken DNS would prevent you from being able to completely login to GNOME? That is what this feels like.
parasubvert 12y ago
This article is at best misguided. OS X 10.10 DNS is not broken, it is working as intended - just differently from the past. Standards have changed and many haven't noticed. All of the bugs cited have to do with ".local" domains. You should never use .local domains as IANA has designated this domain as a special use domain for Multicast DNS as part of IP Zeroconf and Bonjour. http://tools.ietf.org/html/rfc6762 http://tools.ietf.org/html/rfc6762 Apple has also made this clear here: http://support.apple.com/en-us/HT203136 http://support.apple.com/en-us/HT203136 Yosemite has split the job of unicast and multicast DNS up such that you cannot resolve single-label .local domains with unicast DNS anymore; you MUST use multicast. This is why hosts will resolve with nslookup or dig but not ping. The old behavior with mDNSresponder was arguably legacy backwards compatibility for unicast DNS resolution of .local hosts. (I figured this out the hard way over a weekend using the Googles when my local VMs weren't resolving properly via dnsmasq - my fortunes changed when I looked into ".local"). There is one remaining problem with Yosemite DNS I haven't figured out yet, and that's getting unicast DNS resolution via dnsmasq while offline. Frustrating.
- oe 12y ago
  My Yosemite fails frequently resolving common domain names (.com). Has that something to do with .local domains and how could I fix it?
  - nezza-_- 12y ago
    This most likely has to do with your DNS server. Try to change it to another one (e.g. Google's 8.8.8.8 or OpenDNS's 208.67.222.222) and see if it gets better.
  - wolfhumble 12y ago
    Had the same problem popping up just after upgrading to Yosemite. Decided to do a clean install a couple of months ago as I saw other machines on my network didn't have this problem. After the clean install things are working out as expected again. Not what I really wanted (checked quite a bit around for a solution without finding any), but at least I don't have this happening multiple times a day.
NietTim 12y ago
DNS is broken in 10.10? Haven't had a single problem...
- smackfu 12y ago
  That's the problem with networking, right? That the environments you are running in are so diverse that it's nearly impossible to test all the situations. I'm sure that the Apple testers didn't think it was buggy before they released it but a lot of people are having issues in real world situations where the old system worked fine.
untog 12y ago
I've come to the realisation that I don't trust Apple software much these days. I used to upgrade to the latest version of both phone and computer OS quickly, but these days I'll hold on as long as I can - I'm still on 10.9, and waiting for the inevitable software upgrade that will make me have to pull the trigger. I miss the Snow Leopard days.
- rayiner 12y ago
  Yosemite is very solid for me as long as it doesn't have to do with iOS integration. iOS 8 is shit-pure-shit, to the point where even my non-technical mother in law and wife have asked about downgrading. Seriously, random non-technical people I meet talk about how bad iOS 8 is and how they won't upgrade. I haven't seen anything like it since the Windows 9x era.
  - protomyth 12y ago
    Yosemite's Finder is a continuous source of errors (move a lot of files and watch it crash, never mind the reversion in Applescript). It also has some problems with connecting to drives on a server.
    - MrBuddyCasino 12y ago
      I don't know anyone who doesn't have a paus alternative such as Forklift installed. Finder is probably the worst app Apple ever released.
      - protomyth 12y ago
        Well, buying a couple 100 copies of Finder replacements is not seen as a good use of money. Plus, training is an issue.
  - parasubvert 12y ago
    iOS 8 has had problems in early point releases but it's apprently now on 67% of iOS devices. I've found it a bit more stable and usable than iOS 7 but I am on a 5S and 6.
engi_nerd 12y ago
I eagerly await a true fix to 10.10's issues with dropping wifi connections. Both Macbooks in my house running 10.10 drop the wifi connection at least 5x/day, often more. My other devices do not experience these drops, and these same machines were just fine on 10.9. My opinion of Apple's software quality has decreased over the past few months.
- intopieces 12y ago
  Which Macbooks do you have? This hasn't happened to me, but I'd like to know if it might.
  - engi_nerd 12y ago
    I have an early 2011 17" Macbook Pro (8,3). My wife has an early 2009 13" Macbook Pro.
- visarga 12y ago
  My 10.10 used to crash after every VNC session ended. There was no info on Google about this, but there were hundreds of other bugs, seems like everyone has adopted one.
- eridius 12y ago
  Any chance those two MacBooks are connected to a different wifi basestation than your other devices? I have an issue right now where the base station in my living room regularly drops connections (to any devices) but all the other base stations work just fine.
  - engi_nerd 12y ago
    A bit late in seeing this -- but no, I only operate one base station (Netgear AC1900).
    - eridius 12y ago
      And you're running the latest version of OS X 10.10, right? I thought the MBP wifi issues were supposed to be resolved by one of the updates.
visarga 12y ago
I downgraded from 10.10 to 10.9 and now my laptop is faster and crashes much less often. I will probably hold on to 10.9 for a few years. At least on this laptop.
souterrain 12y ago
Note that no one would have clicked on this article if it said "Why mDNS in OS X 10.10 is broken..."
dfcowell 12y ago
What kills me about 10.10 is that OSX doesn't even try to resolve a domain name if you're offline. I run dnsmasq locally, which handles all of my DNS requests, capturing .dev domains (resolving them to 127.0.0.1) and forwarding everything else to Google's servers. This is great as long as I'm connected to WiFi or Ethernet (both are configurable through system preferences) but if I'm travelling and don't have an active network connection - quite frequently, in my case - there's not even an attempt* to hit a DNS server. It just fails. I'm so desperately need a fix to this that I'm wondering if there's some kind of a dongle I can plug into my ethernet or USB port to fake a LAN, just so I can use dnsmasq. The only thing stopping me from wiping out OSX and using Linux full time is the necessity of running Sketch and the Adobe/MS Office suite for work purposes. :/
- sproutworks 12y ago
  I've been using my Zyxel travel router to access the internet with my iMac until the wifi issues are resolved.
- achivetta 12y ago
  Do you have a bug number, by chance? (If not, consider filing one at bugreporter.apple.com)
- realityloop 12y ago
  I posted this issue on hn a week or so ago (https://news.ycombinator.com/item?id=8969581 https://news.ycombinator.com/item?id=8969581).. I tried via AppleCare to escalate this and the response from Apple engineers was that it's expected behaviour.. Also if not for a few key apps I'd be switching to some Linux variant.. Here is a video showing the bug with a comparison of 10.9 and 10.10 https://www.youtube.com/watch?v=3m9OI_AjCx8 https://www.youtube.com/watch?v=3m9OI_AjCx8
MarcScott 12y ago
The networking issues with Yosemite were the final push I needed to shrink it down to a tiny partition and install Linux on my MBP. I'm a very happy MBP user now, and having a tiling windows manager is such a productivity boost, I doubt I'll ever go back.
munchhausen 12y ago
To be fair, innovation and replacing battle-hardened^W^Wobsolete system components with new software that's pushing the envelope comes at a cost. Apple are doing the right thing here and at this pace, I can see OSX being ready for the desktop soon. I'm not replacing my Ubuntu box with a Mac just yet, as some of my core productivity apps have a dependency on DNS, but I'll be keeping a close eye on OSX for sure.

98 points by xvirk 12y ago

webscale2015 12y ago

Author is clearly holding it wrong, it just works, until it doesn't, then the user is still wrong.

I had the "<hostname> is already in use" problem, the safari not able to resolve any hostname and I could not use wake on demand for almost 2 years because of some bug. Maybe I am unusually unlucky but I agree that the quality of the last OS X releases has clearly got worse. The problem with apple software is that if it doesn't "just work" there is little to do about it. I am not so sure about reenabling mDNSResponder. This may cause worse problems.

webscale2015 12y ago
Their software has improved on the mobile front, it seems that's where all their engineers focus these days. It is sad that mac users long for the stability, speed and simple effectiveness of previous versions.
- rnhmjoj 12y ago
  Yes, probably OS X is a bit left aside nowadays.
- protomyth 12y ago
  I wouldn't say that. We are still experiencing the iOS won't connect to wifi bug. The really chaotic thing is that iPhones or iPads of the exact same model and software revision (current iOS 8.1.3) will randomly connect, not connect, or connect long enough to get an ip address then not be able to do anything. It is really getting quite frustrating. We have a Cisco 5807 controller and the 3702e wireless points. Every other OS works just fine. Only having trouble with Apple products and randomly at that.
  - craigching 12y ago
    Agree, having wifi problems myself, pretty much have to restart it on every use and that seems to get me around it until the next time it sleeps. I'm at the point of considering going back to iOS 7 on all my devices.
    - protomyth 12y ago
      I'm just baffled because we have (among tens of other devices) two iPhones with the same model number and one works and one doesn't. I have some students very happy and some very unhappy. Its not like I can get logs from these folks to figure out what the difference is.
- FireBeyond 12y ago
  You don't use third party keyboards, then? Because they regularly break. Swiftype, Swype. Keyboards disappear. All sorts of stuff. And iOS 8 isn't really that much better. I've seen weird screens where all the apps are shown, in different orientations, text rotated while the app maintains a different orientation, in Apple apps and third party.

feld 12y ago

I've seen the Safari hangs -- sometimes it won't even open a new (empty!) tab. I knew it had to be network related, but forgot that discoveryd is in 10.10 or I would have suspected DNS right away. edit: anyone remember how broken DNS would prevent you from being able to completely login to GNOME? That is what this feels like.

parasubvert 12y ago

This article is at best misguided. OS X 10.10 DNS is not broken, it is working as intended - just differently from the past. Standards have changed and many haven't noticed. All of the bugs cited have to do with ".local" domains. You should never use .local domains as IANA has designated this domain as a special use domain for Multicast DNS as part of IP Zeroconf and Bonjour. http://tools.ietf.org/html/rfc6762 http://tools.ietf.org/html/rfc6762 Apple has also made this clear here: http://support.apple.com/en-us/HT203136 http://support.apple.com/en-us/HT203136 Yosemite has split the job of unicast and multicast DNS up such that you cannot resolve single-label .local domains with unicast DNS anymore; you MUST use multicast. This is why hosts will resolve with nslookup or dig but not ping. The old behavior with mDNSresponder was arguably legacy backwards compatibility for unicast DNS resolution of .local hosts. (I figured this out the hard way over a weekend using the Googles when my local VMs weren't resolving properly via dnsmasq - my fortunes changed when I looked into ".local"). There is one remaining problem with Yosemite DNS I haven't figured out yet, and that's getting unicast DNS resolution via dnsmasq while offline. Frustrating.

oe 12y ago
My Yosemite fails frequently resolving common domain names (.com). Has that something to do with .local domains and how could I fix it?
- nezza-_- 12y ago
  This most likely has to do with your DNS server. Try to change it to another one (e.g. Google's 8.8.8.8 or OpenDNS's 208.67.222.222) and see if it gets better.
- wolfhumble 12y ago
  Had the same problem popping up just after upgrading to Yosemite. Decided to do a clean install a couple of months ago as I saw other machines on my network didn't have this problem. After the clean install things are working out as expected again. Not what I really wanted (checked quite a bit around for a solution without finding any), but at least I don't have this happening multiple times a day.

NietTim 12y ago

DNS is broken in 10.10? Haven't had a single problem...

smackfu 12y ago
That's the problem with networking, right? That the environments you are running in are so diverse that it's nearly impossible to test all the situations. I'm sure that the Apple testers didn't think it was buggy before they released it but a lot of people are having issues in real world situations where the old system worked fine.

untog 12y ago

I've come to the realisation that I don't trust Apple software much these days. I used to upgrade to the latest version of both phone and computer OS quickly, but these days I'll hold on as long as I can - I'm still on 10.9, and waiting for the inevitable software upgrade that will make me have to pull the trigger. I miss the Snow Leopard days.

rayiner 12y ago
Yosemite is very solid for me as long as it doesn't have to do with iOS integration. iOS 8 is shit-pure-shit, to the point where even my non-technical mother in law and wife have asked about downgrading. Seriously, random non-technical people I meet talk about how bad iOS 8 is and how they won't upgrade. I haven't seen anything like it since the Windows 9x era.
- protomyth 12y ago
  Yosemite's Finder is a continuous source of errors (move a lot of files and watch it crash, never mind the reversion in Applescript). It also has some problems with connecting to drives on a server.
  - MrBuddyCasino 12y ago
    I don't know anyone who doesn't have a paus alternative such as Forklift installed. Finder is probably the worst app Apple ever released.
    - protomyth 12y ago
      Well, buying a couple 100 copies of Finder replacements is not seen as a good use of money. Plus, training is an issue.
- parasubvert 12y ago
  iOS 8 has had problems in early point releases but it's apprently now on 67% of iOS devices. I've found it a bit more stable and usable than iOS 7 but I am on a 5S and 6.

engi_nerd 12y ago

I eagerly await a true fix to 10.10's issues with dropping wifi connections. Both Macbooks in my house running 10.10 drop the wifi connection at least 5x/day, often more. My other devices do not experience these drops, and these same machines were just fine on 10.9. My opinion of Apple's software quality has decreased over the past few months.

intopieces 12y ago
Which Macbooks do you have? This hasn't happened to me, but I'd like to know if it might.
- engi_nerd 12y ago
  I have an early 2011 17" Macbook Pro (8,3). My wife has an early 2009 13" Macbook Pro.
visarga 12y ago
My 10.10 used to crash after every VNC session ended. There was no info on Google about this, but there were hundreds of other bugs, seems like everyone has adopted one.
eridius 12y ago
Any chance those two MacBooks are connected to a different wifi basestation than your other devices? I have an issue right now where the base station in my living room regularly drops connections (to any devices) but all the other base stations work just fine.
- engi_nerd 12y ago
  A bit late in seeing this -- but no, I only operate one base station (Netgear AC1900).
  - eridius 12y ago
    And you're running the latest version of OS X 10.10, right? I thought the MBP wifi issues were supposed to be resolved by one of the updates.

visarga 12y ago

I downgraded from 10.10 to 10.9 and now my laptop is faster and crashes much less often. I will probably hold on to 10.9 for a few years. At least on this laptop.

souterrain 12y ago

Note that no one would have clicked on this article if it said "Why mDNS in OS X 10.10 is broken..."

dfcowell 12y ago

What kills me about 10.10 is that OSX doesn't even try to resolve a domain name if you're offline. I run dnsmasq locally, which handles all of my DNS requests, capturing .dev domains (resolving them to 127.0.0.1) and forwarding everything else to Google's servers. This is great as long as I'm connected to WiFi or Ethernet (both are configurable through system preferences) but if I'm travelling and don't have an active network connection - quite frequently, in my case - there's not even an attempt* to hit a DNS server. It just fails. I'm so desperately need a fix to this that I'm wondering if there's some kind of a dongle I can plug into my ethernet or USB port to fake a LAN, just so I can use dnsmasq. The only thing stopping me from wiping out OSX and using Linux full time is the necessity of running Sketch and the Adobe/MS Office suite for work purposes. :/

sproutworks 12y ago
I've been using my Zyxel travel router to access the internet with my iMac until the wifi issues are resolved.
achivetta 12y ago
Do you have a bug number, by chance? (If not, consider filing one at bugreporter.apple.com)
realityloop 12y ago
I posted this issue on hn a week or so ago (https://news.ycombinator.com/item?id=8969581 https://news.ycombinator.com/item?id=8969581).. I tried via AppleCare to escalate this and the response from Apple engineers was that it's expected behaviour.. Also if not for a few key apps I'd be switching to some Linux variant.. Here is a video showing the bug with a comparison of 10.9 and 10.10 https://www.youtube.com/watch?v=3m9OI_AjCx8 https://www.youtube.com/watch?v=3m9OI_AjCx8

MarcScott 12y ago

The networking issues with Yosemite were the final push I needed to shrink it down to a tiny partition and install Linux on my MBP. I'm a very happy MBP user now, and having a tiling windows manager is such a productivity boost, I doubt I'll ever go back.

munchhausen 12y ago

To be fair, innovation and replacing battle-hardened^W^Wobsolete system components with new software that's pushing the envelope comes at a cost. Apple are doing the right thing here and at this pace, I can see OSX being ready for the desktop soon. I'm not replacing my Ubuntu box with a Mac just yet, as some of my core productivity apps have a dependency on DNS, but I'll be keeping a close eye on OSX for sure.