Safari DNS problem in Yosemite? Works, then slow death...

I also had the very same problems that are mentioned in this tread...

For me, uninstalling the Cisco VPN client apparently solved the issue.

I had no internet at all yesterday (tried three different networks and everything else in this thread). Then I removed the VPN client and tried another network. for now it's working again. maybe someone is also using the same vpn client?

I can confirm this seems to drastically speed up DNS lookups for my computer.

I have incorporated these commands into a shell script that I will run whenever things get funky:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.discoveryd.plist

sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.discoveryd.plist

sudo discoveryutil mdnsflushcache && sudo discoveryutil udnsflushcaches

MBP 2011, OS X 10.10.3

I have just found this thread because i am tearing my hair out with slow DNS lookup.

I have tried all the suggestions in the thread and it still isnt sorted. I have a new iMac Retina and whenever the mac wakes from sleeping it takes about 30 seconds before any website appears in my browser.

This happens with Safari, Firefox and Chrome.

I am using OpenDNS and have also used GoogleDNS with no improvement.

On this Mac I am connected with a Gigabit Ethernet connection and no wireless. My Macbook also has the same problem and connects via WiFi.

There has been a lot of confusion on certain web discussions, suggesting WiFi adjustments but the fact that my hard-wired iMac is affected shows it has nothing to do with WiFi.

I don't understand all the technical stuff about discoveryd but it sounds as if this is the cause of the problem. My Yosemite version is 10.10.3 and I note earlier commentrs expressing hopes that it will be fixed in 10.10.2 - it isn't!

How do we get Apple to take us seriously on this?

So, I'm going to show my age here, I've been using Mac's since they had little 6 inch green screens and this Yosemite DNS issue the worst Mac problem I've ever encountered. It is even be worse than the dark days of the 7200 series.

I'll start with a positive message to ric_lewis: thank you this helps and clearly does some good.

I'll give you a bit of background. I was running OSX Lion on my Mac Pro and was so frustrated with this OS when I upgraded from (the excellent) Snow Leopard that I couldn't bring myself to even try Mavericks. Eventually the apps I run started demanding Yosemite so I did a clean install (on a new harddrive) and all was well for a fortnight. Then it started.

I'm hard wired into a new Airport Extreme via ethernet but most mornings I can only receive emails (without images) but all my browsers (Safari, Firefox, Chrome) are dead. No connection at all. I found that on the third shutdown and restart the browsers would work. This past week matters have deteriorated further. Within 20 minutes of restarting I lose all browsing capability. Re-boots don't now help, clearing the cache in the browsers doesn't help. I am up and running today as a result of ric's script which I found via my iPad. Incidentally I have to run the script then re-boot my Mac for it to work.

Finally a message to anybody listening from Apple: I've been buying your premium products since the late 1980s. This is the worst issue I've ever seen. How can an organisation of your size and profitability release software that in the year 2015 cannot find the internet? It's embarrassing. I know Yosemite is free, but I'm sure I'm not alone in saying - I'd rather pay for an OS that works than have a free one that falls over. I'm losing 5 hours working time a week on this and I'm starting to think about the benefits of PCs. Please, please, please sort it out.

My Mac is hardwired to my network gateway, but the fact that my iPhone can look up a domain instantly while my Mac times out tells me that it's an OS X problem, and I suspect Yosemite because this problem rarely occurred in 10.7 and 10.8.

Also, nslookup seems to work fine even when the web browsers cannot resolve a domain.

I wish my script was the silver bullet, but it doesn't seem to be the case. It's just a treatment of the symptom because I still experience DNS time outs a few times a day.

I might try having the script run once per hour via launchctl.

Here's something else that points to something seriously amiss somewhere in the OS.

I just fired up my iMac and as usual it refused to connect to the internet and sat waiting to download my home page.

So I tried firing up Parallels running Windows 7 on the same Mac. Chrome under Windows immediately connected and opened my home page and was quick at opening any page I requested.

Back to Yosemite and it was still waiting. I then tried Chrome under Yosemite and same thing - it just sits waiting.

I only moved from Windows PC to Mac last year and I'm seriously wondering if I made the correct decision :-(

Windows is using the same DNS settings as Yosemite (i.e. GoogleDNS)

I've got my "flushcache" script running every hour now. I'll see how it goes today, a regular workday, and let you guys know if there were any DNS timeouts. Because if an hourly script can't fix this problem then may God have mercy on our souls.

I'm now finding even the flushing is hit and miss and multiple re-boots are the only thing that get me going. It's now 3 hours after I started my working day and once again all I've done is re-boot and flush the Mac. This is desperate. I've left polite but firm feedback for Apple on this DNS issue and would encourage others to do the same here:

https://www.apple.com/support/feedback/

I think I'll have to bite the bullet and re-install the OS tonight. Something is badly corrupted and it's beyond the capabilities of Disk Utility.

I've been on the phone to Applecare this morning.

They got me to do two things:

1) Create a new network location

2) Rename the System Configuration folder

I couldn't quite see the point of step 1 when step 2 lost the changes I'd made in step 1 but anyway I went along with it and for now it is working much better. BUT as we all know this may well be temporary improvement. Fingers crossed. They are ringing me back in a couple of hours

Thanks for posting this I've just read a similar fix that involves back up the SystemConfiguration foler and then deleting the contents of the old one.

Did they ask you to rename the folder to anything specific?

I renamed it to SystemConfiguration-old. After rebooting, a new SystemConfiguration folder was created,

It seems to be OK so far.

Much appreciated, I've got it running today, but doubtless tomorrow morning Yosemite won't be able to find the world wide web, at which point I'll try this.

Thanks for your help.

Yeah, I've already left feedback on that official Apple link.

I think having the script run hourly has alleviated the symptom of DNS timeouts.

However, I did experience one thing today that was totally new: complete loss of internet connection (the network connection showed only a locally assigned IP address). Admittedly, I have the ethernet cable plugged into a Thunderbolt display, and not directly into the laptop.

I eventually 'fixed' it by unplugging the re-plugging the ethernet cable (both on the display and at the router). I'm hoping that never happens again because I have enough trouble on my hands with DNS timeouts to start losing internet entirely (DNS timeouts seem to occur on a per-domain basis).

I have already once tried deleting the SystemConfiguration folder – it just caused me to lose all my network configs (like my VPN) and I had to set them up again, but the DNS timeouts returned.

chownz, I would be surprised if a re-install fixes the problem – my laptop had a 100% clean install in February of this year. Did not make a difference.

I've been seeing this on my computers and on my phone. Just spins, page never loads. If I turn it off, turn it on sometimes it works. But bouncing between multpile networks at other locations it just seems to get stuck sometimes. Starting to wonder if there is some lint building up in the iCloud sync stuff. This may be why it screws up a new OS install or computer too.

It's a bit early to get too excited but since I renamed the SystemConfiguration folder as advised by Applecare, I have had no DNS hangs. I am not celebrating till I have tested it for several more days but this would normally have played up by now. Fingers crossed.