DNS issues after 10.6.5 update

10.6.6 didn't fix it for me but your patch did!
mDNSResponder is up without any problem for 30 minutes now.
Thanks!

Message was edited by: bencall

Problem is still there in fact 😟

Sorry for posting, but i wanted to update my "status".

I just reinstalled de combo 10.6.6 update.
The mDNS, mDNSResponder, etc... have been modified (seen in the finder), but nothing works...

Reinstalling the entire OS and make a save before installing 10.6.5 seems the only solution for me...

Any news regarding this issue?

I have unfortunately the same problem since update to 10.6.5. Even the latest update to 10.6.6 didn't fix this problem.

I don't think that anything changed with respect to the mDNS binaries from 10.6.5 to 10.6.6. I've been running with 10.6.6 though for a little while now and have not had a complete mDNSResponder hangup. I did update my Parallels install too, which may have played a part in all this.

bencall wrote:
Problem is still there in fact 😟

I installed this patch and a whole host of problems disappeared. My system seems perfectly normal now.

NOTE: You need to boot by holding down the power button until you hear the long-gong, then let it go. I'm not exactly sure what this does, but I think it forces a refresh of all the boot caches and other mysterious stuff.

KJK555: Many thanks, your fix worked for me.
We use manual IP slightly unusal for historical reasons as 169.254.0.xxx behind a PC using winproxy with two ethernet cards.
We order 4 mac mini in Juliet 2010 and all the internet connection were broken with update 10.6.5 and now with 10.6.6
We also update a MacBook Air to 10.6.6 because its USB inside camera does not work.
So for these 5 stations your fix works perfectly.
Thank you so much to save our situation.
We are only slightly afraid for the next update because i'm not sure Apple modify something. Apple support was no help for that and they say they are ignorant about this trouble.
Pierre

I too was having some difficulty with DNS after updating to 10.6.5 and 10.6.6. The problem manifested itself at work/school where I have a Mac OS X server (10.4.x) inside a private network (192.168.xxx.xxx) running a Moodle. The OS X server also does dns and is the dhcp server. I use a bogus domain name for the server because it is not accessible to the outside world. In the past I had no problems accessing the server from my Macbook by using the bogus domain name. However, after I updated the Macbook to 10.6.5 I would be able to access the server and log into the Moodle, browse around a little, then have Safari say it couldn't connect because the server couldn't be found. Lookup and ping would work, but nothing from Safari. If I put in the ip address instead of the name, in Safari it would connect. Usually if I waited a few minutes and tried again it would work. It was rather maddening, on again, off again.
I think I have "fixed" the problem with a work around. I edited the hosts file on my Macbook to include an entry for the bogus domain name and the private IP address of the server.

Is there any solution to this issue? I have tried suggestions here without luck. I'm back using 10.6.4 which works perfectly. When I updated to 10.6.5, all browsers would hang with the beachball and not responding, and I had to force quit. Same issue when I tried 10.6.6. The system would work for various periods of time, from a few minutes to several hours before the problem would come up. Once browsers would hang, I could not shut down or restart through the menu, even though I force quit the not responding applications. I had to hold the power button to shut down. I tried everything suggested here and more, including a total clean install and removing all hard drives other than the boot drive and removed all peripherals except displays. I tried direct-connect to internet with the cable modem rather than through my Airport. I tried tethering to my iPhone. I tried using googles DSN settings. I have a three year old Mac Pro 2x3GHz Dual-Core Intel Xeon, 4GB 667 MHz DDR2 FB-DIMM. I set up a case before my AppleCare expired two weeks ago, but the suggested solutions failed to solve the issue.

DarkKent i am in the same exact situation with a 3years macbook 2.2 santarosa.
No update to the topic?

We have had mDNSResponder stop supply DNS results a number of times - especially with the SonicWall NetExtender VPN client. This can even cause your Mac to hang at the gray startup screen with the spinning icon. The only fix that works every time has been to issue the following launchctl commands which to need to be run as an admin (I don't personally run as an admin on my personal Mac).

sudo launchctl unload /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist

and

sudo launchctl unload /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist

This seems to cause mDNSResponder to reload its configuration and come alive. We even went so far as to script this into cron for a few trouble MacOSX boxen. Final report: no more problems with mDNSResponder.

Do these commands work for you too?

Rurik

Rurik, yours is the first and only suggestion that has corrected the problems I was seeing. Namely, the machine would boot and DNS was already failing. Network connectivity works, but DNS would not resolve.

By using launchctl to unload and load mDNSResponder, the problem was fixed.

BTW, we have also been suffering through dozens of gray startup screens in the last couple months. Only in the last week or so have we identified NetExtender as a possible culprit. Thanks for some additional confirmation.

This gives me two questions.

First, why do I need to perform the unload/load sequence immediately after startup on one particular machine?

Second, can these commands be used in single-user mode to rescue a machine that has become stuck at the gray startup screen?

Thoughts?

First, why do I need to perform the unload/load sequence immediately
after startup on one particular machine?

I don't know why it affects some machines and not others.

Second, can these commands be used in single-user mode to rescue a
machine that has become stuck at the gray startup screen?

Yes, they can be run in single-user mode. Short version:

- Boot into single user mode
# can run fsck, probably always a good idea
- mount -uw /
- execute commands above.
- exit

The Mac will now boot properly (at least I've never had it fail yet). When I have started in verbose mode, it shows it's waiting for eth0, when it is actually waiting for mDNS - go figure on that one.

Enjoy!

Rurik

for me is not working:
sudo launchctl unload /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
sudo launchctl load /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist

if the net stucks and i try to enter in terminal "sudo launchctl unload /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist" i enter the pass and nothing happen it's like the command don't success because the promp don't appear again 😟

Sounds like you have a different problem. Are you in single-user mode, regular startup?