If mDNSResponder is getting out of hand you can unload it,
noting that mDNSResponder is part of OSX's DNS resolution, and therefor network discovery (LAN, WAN etc) requires it (at least to some degree - I need to research more - so, not knowing, I've not unloaded it);
ie. no mDNSResponder, no resolving host names.
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
To turn it back on, just do the opposite:
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist
