Weird DNS issue when waking from sleep

Conanius

Conanius

Conanius

Soldato
Joined
18 Oct 2002
Posts
12,740
Odd one.

When our Macbook Air wakes from sleep (so closing the lid) it seems to take upwards of a minute to be able to resolve DNS.

I get very quick WiFi connectivity (To an AC WiFi Time Capsule which is our main WiFi point in the house) and using Terminal I can ping our DNS server no problem (google, 8.8.8.8).

Any ideas what on earth could be the cause?

edit - looks like I'm not on my own - http://arstechnica.com/apple/2015/01/why-dns-in-os-x-10-10-is-broken-and-what-you-can-do-to-fix-it/

I've also read having hard disks going to sleep can cause it if there is an SSD. Not sure how. As this used to be a MacBook Pro with a HDD, and its now been restored onto this Macbook Air with SSD, I've disabled that function, we'll see how it goes.
 
Last edited:
Conanius said:
Odd one.

When our Macbook Air wakes from sleep (so closing the lid) it seems to take upwards of a minute to be able to resolve DNS.

I get very quick WiFi connectivity (To an AC WiFi Time Capsule which is our main WiFi point in the house) and using Terminal I can ping our DNS server no problem (google, 8.8.8.8).

Any ideas what on earth could be the cause?

edit - looks like I'm not on my own - http://arstechnica.com/apple/2015/01/why-dns-in-os-x-10-10-is-broken-and-what-you-can-do-to-fix-it/

I've also read having hard disks going to sleep can cause it if there is an SSD. Not sure how. As this used to be a MacBook Pro with a HDD, and its now been restored onto this Macbook Air with SSD, I've disabled that function, we'll see how it goes.
Click to expand...

The DNS issue should be resolved officially in the next update to OS X. (10.10.4)

http://www.macrumors.com/2015/06/09/apple-seeds-fifth-yosemite-10-10-4-beta/
 
Apple replaced an under the hood service called mDNSResponder with something else that did the same job called discoveryd in Yosemite. Frankly it's just rubbish, I've no idea what was wrong with the solution they'd been using for well over 10 years!

Anyway, the good news is that mDNSResponder is back in 10.10.4. Public Beta is available now if you want to sign up. It's fixed all the intermittent DNS and networking issues I was having. No more Magic's Mac Mini (9) appearing in Finder that I'm unable to connect to. No more borked Wake on demand. Even Bonjour is working.
 
this has gotten exponentially worse in the last few weeks. The laptop is taking nearly 10 minutes to get DNS resolution now.

Any ideas on a quick fix?
 
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