Possible DNS issue with Yosemite

rohin

macrumors newbie
Original poster
Aug 20, 2014
1
0
Since upgrading to Yosemite I've been having weird network issues. I'm assuming it is something DNS related.

I can access any website just fine using the browser, but most network terminal commands fails. E.g. ping google.com returns

ping: cannot resolve google.com: Unknown host

However nslookup google.com works just fine and returns a list of servers with ip addresses. Then if I ping one of those ip addresses it works just fine.

As a temporary solution for now I've added entries to /etc/hosts for server addresses that I use often.

It seems to sort of work, but I have to restart my mac each time I make a change to /etc/hosts for the change to take effect.

At this stage I'm thinking the best and fastest solution might be to do a complete reinstall of Mountain Lion and then wait until Yosemite is officially released before upgrading.

Thoughts?
 

jg321

macrumors 6502
Aug 29, 2012
292
6
UK
13" rMBP here. 5Ghz to APE. Whenever I cold boot DP6, DNS doesn't resolve for the first 10 mins or so. Eventually, with no action from me, it just starts working.

This is a weird hybrid from PB1 to DP5 to DP6 though, so that can't be helping any! Tempted just to fresh install PB2.
 

joedec

macrumors 6502
Jul 25, 2014
405
25
Cupertino
13" rMBP here. 5Ghz to APE. Whenever I cold boot DP6, DNS doesn't resolve for the first 10 mins or so. Eventually, with no action from me, it just starts working.

This is a weird hybrid from PB1 to DP5 to DP6 though, so that can't be helping any! Tempted just to fresh install PB2.
I would seriously doubt this is Yosemite related. I have a few different releases running and DNS works fine. Keeping in mind I have really good network access.

I would not use 'ping' for testing since a lot of sites disable those requests. Use either 'nslookup' or 'dig'. For example;

$ dig google.com

If you continue to have slow name resolution there is a tool you use can use to test known DNS servers with your location, then give you a recommendation.

https://code.google.com/p/namebench/

Once you find the optimal server you can set that in

System Preferences/Network/Advanced/DNS

Of course if your network is slow for some other reason DNS will suffer as well.
 
Last edited:

jg321

macrumors 6502
Aug 29, 2012
292
6
UK
I would seriously doubt this is Yosemite related. I have a few different releases running and DNS works fine. Keeping in mind I have really good network access.

I would not use 'ping' for testing since a lot of sites disable those requests. Use either 'nslookup' or 'dig'. For example;

$ dig google.com

If you continue to have slow name resolution there is a tool you use can use to test known DNS servers with your location, then give you a recommendation.

https://code.google.com/p/namebench/

Once you find the optimal server you can set that in

System Preferences/Network/Advanced/DNS

Of course if your network is slow for some other reason DNS will suffer as well.
Thanks. It is DNS, and does appear to be Yosemite related. Happened again last night, thought I'd flush the cache. Turns out the mDNSResponder service wasn't running at all!

Started this, and working immediately. Wouldn't be surprised if it was to do with the PB1 -> DP5 -> DP6 -> PB2 path I've taken.

Appreciate the comments about networks blocking ICMP requests, but as I say, my issue was with resolution, no matter what the tool to request that resolution is. I realise others may not be so specific when they say "resolution".

In any case, problem appears to be less frequent with PB2.

Edit - just to add, no DNS/Internet issues on 3 other Macs running Mavericks, two iPhones and an iPad, which is why this appears to be Yosemite related.
 

joedec

macrumors 6502
Jul 25, 2014
405
25
Cupertino
Thanks. It is DNS, and does appear to be Yosemite related. Happened again last night, thought I'd flush the cache. Turns out the mDNSResponder service wasn't running at all!

Started this, and working immediately. Wouldn't be surprised if it was to do with the PB1 -> DP5 -> DP6 -> PB2 path I've taken.

Appreciate the comments about networks blocking ICMP requests, but as I say, my issue was with resolution, no matter what the tool to request that resolution is. I realise others may not be so specific when they say "resolution".

In any case, problem appears to be less frequent with PB2.

Edit - just to add, no DNS/Internet issues on 3 other Macs running Mavericks, two iPhones and an iPad, which is why this appears to be Yosemite related.
Yes, I see what you mean, that is a convoluted update path, who knows, the service not running is key.

Isn't is great to have multiple machines, takes the guess work out of network troubleshooting.
 

jg321

macrumors 6502
Aug 29, 2012
292
6
UK
Yes, I see what you mean, that is a convoluted update path, who knows, the service not running is key.

Isn't is great to have multiple machines, takes the guess work out of network troubleshooting.
Yeah, indeed! Should really reinstall this, but when the GM is so close, I'm likely just to wait until that is released then do a clean install.

Was sort of forced into the crazy path; hit an actual bug where it'd take minutes to boot on PB1, and DP5 fixed that immediately.
 

benthewraith

macrumors 68040
May 27, 2006
3,073
80
Miami, FL
Thanks. It is DNS, and does appear to be Yosemite related. Happened again last night, thought I'd flush the cache. Turns out the mDNSResponder service wasn't running at all!

Started this, and working immediately. Wouldn't be surprised if it was to do with the PB1 -> DP5 -> DP6 -> PB2 path I've taken.

Appreciate the comments about networks blocking ICMP requests, but as I say, my issue was with resolution, no matter what the tool to request that resolution is. I realise others may not be so specific when they say "resolution".

In any case, problem appears to be less frequent with PB2.

Edit - just to add, no DNS/Internet issues on 3 other Macs running Mavericks, two iPhones and an iPad, which is why this appears to be Yosemite related.
Why did you go from DP6 to PB2?
 

umangd

macrumors newbie
Sep 17, 2014
5
0
I am facing the same issues. Both the mdnsresponder plist and /usr/sbin/mdnsresponder are missing in PB3! Any idea how to fix it?
 

erikssone

macrumors newbie
Sep 16, 2014
5
0
I am facing the same issues. Both the mdnsresponder plist and /usr/sbin/mdnsresponder are missing in PB3! Any idea how to fix it?
I think mDNSResponder have been replaced by the dnsdiscoveryd service but I'm no where near an expert on this so what that means I have no idea.
 

umangd

macrumors newbie
Sep 17, 2014
5
0
I have tried flushing cache with sudo discoveryutil mdnsflushcache, and still its not working! :(
 

snarfquest

macrumors regular
Jun 7, 2013
210
4
The new way to flush dns cache seems to be:

sudo discoveryutil udnsflushcaches

Note that it is plural. It seems to take it as udnsflushcache however as a valid command.... but, I've noticed that only udnsflushcaches does what I want it to do.
 

erikssone

macrumors newbie
Sep 16, 2014
5
0
The new way to flush dns cache seems to be:

sudo discoveryutil udnsflushcaches

Note that it is plural. It seems to take it as udnsflushcache however as a valid command.... but, I've noticed that only udnsflushcaches does what I want it to do.
It feels like I've tried everything possible without any luck.
It's almost like that something is completely missing or not connected as it should on some versions of Mac computers.

Like I said - almost flawless on my Macbook Pro (I sometimes have to wait a minute after reboot or wake from sleep, otherwise ok). But on my iMac - it NEVER works no matter what I try. Pinging external or internal ip-adresses works like a charm. Even nslookup resolves names but every other application that connects to a network seems broken.

Therefore I just reverted to Mavericks from a TimeMachine backup. Let me know if you find a solution or if a new beta release solves this issue.

/Erik
 

erikssone

macrumors newbie
Sep 16, 2014
5
0
Hi

Tried a clean install of Ysemite GM Preview and then I have working networking. But as soon as I restore users, settings, applications and so on the issue reappears. Seems as if "upgrading" to Yosemite is the culprit for me.

Don't know what this tells you but I can't think anyone of you being dumber than me so hopefully it's a clue.
 

Spark-MR

macrumors newbie
Oct 2, 2014
3
0
I noticed that this connectivity issue occurred on accounts where Parent Controls was enabled. If you have Parent Controls turned on for the account that's having connectivity issues, try disabling that.
 

Spytap

macrumors regular
Oct 8, 2010
121
66
No parent controls here, but the same DNS issues. Installed DP8 from Mavericks, and then recently upgraded to GM. Only having the DNS issues in GM.
 

Olig23

macrumors newbie
Oct 14, 2014
2
0
Ditto. I loose DNS resolution after upgrading to PB3 or PB4 and resolve it by downgrading to PB2. I'm pretty sure it relates to mDNSResponder since the service is dropped after PB2. But can it be run on PB3 onwards? I don't really want to clean install but could as a last resort.
 

zivagolee

macrumors newbie
Oct 17, 2014
1
0
i have this issue as well and removing my /etc/resolver and restarting the network interface works now. however, now i don't have my domain search expansion :(
 

Olig23

macrumors newbie
Oct 14, 2014
2
0
I'm not technical enough to resolve it. I download developer GM candidate 1 and completed a fresh install. Problem solved but crappy solution.