Why is discoveryd invoking the non-existent /var/run/mDNSResponder file?

cdhw: Thanks for your input.

I got the same results as you using terminal to confirm that mDNSResponder still existed. Oddly, when navigating to //var/run/mDNSResponder in finder, it does not appear, which is what prompted my inquiry.

I had deleted the preferences.plist before, but I did it again on all three computers on my network. Did not solve the delays and failures in resolving web pages.

The /private/etc/hosts file is the default.

Mr. Davis:

I performed the tests you suggested. Regarding the first test, I have the problem when logged in as Guest.

Test 1

Using Safari, after 7 seconds, it reported that Safari could not open "https://google.com/search." Safari is rather annoying in that once the dns lookup fails, Safari refreshes to the failure page, not the original url, unless you click within the address bar (and that only works sometime). Nevertheless, Safari could navigate to www.philly.com. After 60 seconds, the page loaded incompletely. It had some text, but pictures, videos and ads did not load. Moreover, links appear, but they do not function when I click upon them. If I alternative click on them and open in a new tab, the linked page loads. If I load the home page, then reload the home page, the links become clickable. Even then, some links to different domains result in complete page-load failures.

Using Google Chrome, there were still some complete failures of dns lookup, but these could be resolved by clicking the refresh button. The times to full page loading ranged from quick (2 seconds) to ridiculous (2:45 minutes). A pages' text may be readable quickly, but picture, ads and videos, take minutes to fully load. sometimes only after refreshing the page. Tracking resolution using chrome://net-internals/#events&q=type:HOST_RESOLVER_IMPL_JOB%20is:active reveals that individual addresses each may take seconds to resolve, and when they do, they hold up the resolution of other pending lookup. Even if a page become readable, Chrome is taking minutes to fully resolve the links on the page as shown by the unresolved list in the Chrome net-internals page and the message (Resolving host . . .) which appears in the lower left of the target page browser window.

Test 2

Booting the server or a client laptop in safe mode (after flushing the dns caches in the OS and in Chrome), results in essentially the same behaviors. Safari dns look up times out, and repeated manual refreshes are required to get pages to load partially or fully. Chrome will load pages but in Safe Mode it flickers with each resolution of a component. Thus, Chrome will flicker for 30 seconds to 2 minutes until it appears stable, and any click will reintroduce the flicker for a period.

Other

I have examined the dns logs (performing a "tail -f /Library/Logs/named.log" and examining the DNS service log in Server 4 appear to be equivalent). There are massive amounts of errors for every page load. IPv6 queries report "error (host unreachable) resolving xxx.xxx.xxx.:53." IPv4 queries report "error (connection refused) resolving xxx.xxx.xxx.:53". The connections are being refused by Google (8.8.8.8 and 8.8.4.4), my forwarding dns lookups, as well and verisign and many many others. Yet, with delays, I do get DNS resolution of outside webpages.

I am running a Yosemite Server on an iMac, with two other Yosemite machines on the network. The network is behind a Netgear firewall and a Comcast Cable modem. Except for the Netgear, none of the machines are running a firewall. Port 53 is open under both the UDP and TPC protocols. The forwarding DNS lookups are set to Google in all the machines.

I ran this test, after flushing the mdns cache and udns cache. Before rebooting in Recovery mode to use Safari, I attempted to visit Netlix.com. The site loaded, but without applying the css to format the page. In Recovery Mode, Safari loaded Netflix properly, but after a delay of about 15 seconds. Thereafter, Safari was initially very fast, loading Huffington Post and Philly.com quickly. Performance then deteriorated within minutes, with fast loading of functional pages becoming sporadic. Some sites still took up to a minute to resolve. Reloads were necessary for full resolution of page content and the reloads took 15-30 seconds to display anything, which was often longer than the initial, partial load time. Generally, Safari functioned better in Recovery Mode than it does in normal mode, but there were still problematic delays.

EtreCheck version: 2.2 (132)

Report generated 5/26/15, 7:32 PM

Download EtreCheck from http://etresoft.com/etrecheck

Click the [Click for support] links for help with non-Apple products.

Click the [Click for details] links for more information about that line.

Hardware Information: ℹ️

iMac (27-inch, Mid 2011) (Technical Specifications)

iMac - model: iMac12,2

1 2.7 GHz Intel Core i5 CPU: 4-core

16 GB RAM Upgradeable

BANK 0/DIMM0

8 GB DDR3 1333 MHz ok

BANK 1/DIMM0

8 GB DDR3 1333 MHz ok

BANK 0/DIMM1

Empty

BANK 1/DIMM1

Empty

Bluetooth: Old - Handoff/Airdrop2 not supported

Wireless: en1: 802.11 a/b/g/n

Video Information: ℹ️

AMD Radeon HD 6770M - VRAM: 512 MB

iMac 2560 x 1440

System Software: ℹ️

OS X 10.10.3 (14D136) - Time since boot: 2:37:12

Disk Information: ℹ️

ST31000528AS disk0 : (1 TB)

EFI (disk0s1) <not mounted> : 210 MB

Macintosh HD (disk0s2) / : 999.35 GB (71.72 GB free)

Recovery HD (disk0s3) <not mounted> [Recovery]: 650 MB

HL-DT-STDVDRW GA32N

ST4000DX000-1CL160 disk1 : (4 TB)

EFI (disk1s1) <not mounted> : 210 MB

LaCie (disk1s2) /Volumes/LaCie : 4.00 TB (1.49 TB free)

USB Information: ℹ️

Western Digital My Passport 0746 1 TB

EFI (disk3s1) <not mounted> : 210 MB

My Passport (disk3s2) /Volumes/My Passport : 999.83 GB (168.26 GB free)

Apple, Inc. Keyboard Hub

SanDisk SDDR-189

Apple, Inc Apple Keyboard

Apple Internal Memory Card Reader

Apple Computer, Inc. IR Receiver

Apple Inc. FaceTime HD Camera (Built-in)

HewLett Packard HP LaserJet 1200

Apple Inc. BRCM2046 Hub

Apple Inc. Bluetooth USB Host Controller

Firewire Information: ℹ️

HGST G-DRIVE 800mbit - 800mbit max

EFI (disk2s1) <not mounted> : 210 MB

G Tech 4TB (disk2s2) /Volumes/G Tech 4TB : 4.00 TB (65.63 GB free)

Thunderbolt Information: ℹ️

Apple Inc. thunderbolt_bus

LaCie d2

Gatekeeper: ℹ️

Mac App Store and identified developers

Kernel Extensions: ℹ️

/Volumes/My Passport/Applications/VMware Fusion.app

[not loaded] com.vmware.kext.vmci (90.4.19) [Click for support]

[not loaded] com.vmware.kext.vmioplug.10.1.26 (10.1.26) [Click for support]

[not loaded] com.vmware.kext.vmnet (0194.56.92) [Click for support]

[not loaded] com.vmware.kext.vmx86 (0194.56.92) [Click for support]

[not loaded] com.vmware.kext.vsockets (90.4.24) [Click for support]

Problem System Launch Daemons: ℹ️

[failed] com.apple.mtrecorder.plist

Launch Agents: ℹ️

[not loaded] com.adobe.AAM.Updater-1.0.plist [Click for support]

[loaded] com.adobe.CS5ServiceManager.plist [Click for support]

[loaded] com.google.keystone.agent.plist [Click for support]

[loaded] com.oracle.java.Java-Updater.plist [Click for support]

Launch Daemons: ℹ️

[loaded] com.adobe.fpsaud.plist [Click for support]

[not loaded] com.adobe.SwitchBoard.plist [Click for support]

[failed] com.apple.spirecorder.plist

[loaded] com.google.keystone.daemon.plist [Click for support]

[loaded] com.oracle.java.Helper-Tool.plist [Click for support]

[loaded] com.oracle.java.JavaUpdateHelper.plist [Click for support]

User Launch Agents: ℹ️

[loaded] com.adobe.AAM.Updater-1.0.plist [Click for support]

[loaded] com.adobe.ARM.[...].plist [Click for support]

User Login Items: ℹ️

Mail Application Hidden (/Applications/Mail.app)

Dropbox Application Hidden (/Applications/Dropbox.app)

Internet Plug-ins: ℹ️

FlashPlayer-10.6: Version: 17.0.0.188 - SDK 10.6 [Click for support]

QuickTime Plugin: Version: 7.7.3

Flash Player: Version: 17.0.0.188 - SDK 10.6 Cannot contact Adobe

AdobePDFViewer: Version: 9.5.5 [Click for support]

Default Browser: Version: 600 - SDK 10.10

Silverlight: Version: 5.1.30514.0 - SDK 10.6 [Click for support]

JavaAppletPlugin: Version: Java 8 Update 45 Check version

3rd Party Preference Panes: ℹ️

Flash Player [Click for support]

Java [Click for support]

Time Machine: ℹ️

Skip System Files: NO

Mobile backups: OFF

Auto backup: NO - Auto backup turned off

Volumes being backed up:

Macintosh HD: Disk size: 999.35 GB Disk used: 927.62 GB

Destinations:

My Passport [Local]

Total size: 999.83 GB

Total number of backups: 0

Oldest backup: -

Last backup: -

Size of backup disk: Too small

Backup size 999.83 GB < (Disk used 927.62 GB X 3)

Top Processes by CPU: ℹ️

22% Google Chrome Helper(5)

6% WindowServer

5% Google Chrome

2% python(3)

2% fontd

Top Processes by Memory: ℹ️

1.08 GB kernel_task

901 MB ruby(12)

705 MB Google Chrome Helper(5)

311 MB clamd

246 MB mdworker(8)

Virtual Memory Information: ℹ️

6.25 GB Free RAM

9.74 GB Used RAM

0 B Swap Used

Diagnostics Information: ℹ️

May 26, 2015, 04:51:56 PM Self test - passed

Standard users cannot read /Library/Logs/DiagnosticReports.

Run as an administrator account to see more information.

I intentionally surfed the web while this test was running. Note that Google chrome helper puts a 22% drain on the cpu. That seems to me to indicate that DNS resolution is not efficient.

This ultimately was a problem with a misconfigured router. The problematic router, a Netgear wireless router, had not been configured with the routers preset DNS settings (DNS:UDP & DNS:TCP). Rather, the only DNS setting put in the router were manual forward of port 53 (UDP) and port 53 (TCP). That allowed the internet to get the server's SOA but was confounding the OS's and Chrome's resolvers. Unlike the preset that existed in the router, the manual set up failed to open the high numbered ports through which the DNS resolvers worked their magic. The problem was diagnosed by substituting a different router (same model, but not wireless), which immediately opened the high numbered ports and resolved the issue. On the wireless model, the presets services were a little hidden: they are accessed by clicking the "Add," not on the services tab, but directly on the rules tab. Once that was discovered, and the presets for DNS were invoked and the manually created DNS forwards were disabled, DNS resolution functioned properly on both routers. The bottom line is that the DNS presets open more than just port 53, and are necessary for the efficient functioning of the DNS resolvers within OS X 10.10.3 Yosemite and the DNS resolver internal to Google Chrome.

This resolved the following error message:

"error (connection refused) resolving [webaddress]#53"

It also eliminated the traffic jam of unresolved addresses in Google Chrome's resolver that would appear here:

chrome://net-internals/#events&q=type:HOST_RESOLVER_IMPL_JOB%20is:active

Thanks to everyone who took the time to help me with this problem.