Possible DNS issue with Yosemite

[rohin]

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?

 

[bowler357]

I also seem to be noticing the same behavior. So far a reboot is the only way I've found to flush it.

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Could be related. I'll try flushing via Terminal next time it happens. https://forums.macrumors.com/threads/1750661/

 

[DJEmergency]

I've been having DNS issues for a long time before 10.10...

 

[jg321]

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]

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.

 

[jg321]

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]

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]

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]

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?

 

[jg321]

Why did you go from DP6 to PB2?

No real reason tbh. I'd already started on the convoluted path, so wasn't a big deal continuing! No deal breaking issues though.

 

[erikssone]

Not sure your upgrade path causes this

I'm just a "curious" beta tester who has upgraded from Mavericks to 10.10 B1, B2 and just B3.

Look at my problem https://forums.macrumors.com/showthread.php?p=19719473#post19719473

 

[umangd]

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]

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]

I have tried flushing cache with sudo discoveryutil mdnsflushcache, and still its not working!

 

[snarfquest]

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]

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

 

[bighans]

I have the same problem is there a way to get back MDNSresponder?

 

[erikssone]

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]

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]

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]

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]

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]

I'm not technical enough to resolve it. I download developer GM candidate 1 and completed a fresh install. Problem solved but crappy solution.