I have been using dnsmasq on mac osx mountain lion which was installed via mac ports. Recently,I upgraded to Osx Mavericks and all of a sudden it has stopped working.
I
I had issue with DNS after upgrade, in which is just wouldn't start from UI. Not using DNSMASQ myself, though you could look at this to see if is connected to your problem.
https://discussions.apple.com/message/23469825#23469825
Edit (as root) plist at /var/db/launchd.db/com.apple.launchd/overrides.plist
Look for
Set value of
to
.