Any OSX Power users?

Grant Shipley gshipley at gmail.com
Tue Dec 10 22:00:18 MST 2013


I know this is a linux list but I am at the end of my rope on this one.  I
can't for the life of me figure out how dns resolution works in OSX
Mavericks 10.9.

Scenario:

I have a PaaS setup in a test environment on openstack and I used the
domain name of example.com for my domain.  This is fine as I setup a bind
dns server to resolve all of those hosts for me.  On windows and linux its
as easy as adding the dns server I created to the top of the list in
/etc/resolv.conf.

Enter OSX.

First of all, /etc/resolv.conf isn't respected on the mac so you have to
add manual entries of dns server in the network gui.  I did this but it
still doesn't work.  dig returns the right info and pulls it from my dns
server.  ping returns different results.  I start to pull my hair out.

So then I google for about 19 straight hours and find that DNS on OSX uses
mDNSResponder.  And I then found this little nugget:

https://discussions.apple.com/message/10546115#10546115

"
2) mDNSResponder does not honor DNS server ordering

While not explicitly documented, in Mac OS X versions earlier than Snow
Leopard, DNS servers, whether specified manually or via DHCP, were queried
in the order they were provided. For manual specification, this means in
the order shown in the appropriate Network preferences pane tab, and for
DHCP users in the order specified by the DHCP server.

This is no longer true in Mac OS X Snow Leopard; instead mDNSResponder now
seems to occasionally change the order in which it queries DNS servers from
that in which they were specified.
"

Great.  Thanks for not respecting the order Apple.  I enjoy putting my dns
servers on a dart board and seeing which one I hit.

So then I find another little nugget that says you can override this by:

sudo /usr/libexec/PlistBuddy -c "Add :StrictUnicastOrdering bool true"
/System/Library/LaunchDaemons/com.apple.mDNSResponder.plist


Yeah, well that doesn't work either.

So anyone know how to enforce dns ordering on OSX?

And before you suggest I don't use OSX, I don't have a choice for this
particular job.

Any help is appreciated.

--
gs


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