Deanspot.org

We upgraded Sara's iMac to OSX 10.6. Mostly this is fine, but a few things are broken. Local DNS was one main problem. We have all our local machines in the '.dean' domain, and while I was able to correctly look up these names using dig, I wasn't able to actually use them in Firefox, ssh, or any other program.

The problem seems to be that 10.6 does not respect a DNS response with a TTL (time to live) of 0, which is the default value used by DNSMasq, the DNS/DHCP server which we use as part of DD-WRT.

The problem is described in this thread, in a posting by 'hphoto' dated '09-22-2009, 04:25 PM'.
http://www.mac-forums.com/forums/os-x-operating-system/164649-snow-leopa...

The advice seems to be right-on. Raising the TTL to some non-0 value for local DNS seems to solve the problem. I chose 5 seconds for mine.

Notice the '0' in the ANSWER SECTION. That's the TTL.

Now go to the DD-WRT admin page for DNS options:

And add a 'local-ttl' value.

Then save your options.

These pages were useful for reference.
http://www.dd-wrt.com/wiki/index.php/DNSMasq_as_DHCP_server
http://www.thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html

Notice that the options in the man page seem to be usable by just dropping the '--' from the long version of the option. So '--local-ttl=5' in the command-line version becomes just 'local-ttl=5' in the DD-WRT web interface.

Now, you can re-try that dig query to see the changed value.

Hope that helps!