I recently upgrades to Leopard and the operating system has been great. After installing my core set of programs, I noticed that mDNSResponder was going nuts. Being that I am on an university network, there are hundreds on the current sub-network. By default, Leopard has a “feature” that lists all the local computers (windows or mac) that it finds. This is called Bonjour. You may know about this via iChat, or other programs. Sure, that’s nice, but does it take up lots processes. Again, this would be nice upon request, but the task is done repeatedly. The load on your system just gets out of hand.
After some research, I found that there is a Launch Daemon for this. Here’s how you turn it off, but don’t worry, you can turn it back on anytime, without restarts or anything.
Load up Terminal (Applications > Utilities > Terminal.app) and type the following.
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
you can turn it off in finder prefs.
@Bill Bratches: Actually, doing that will just hide the display. The process is still running in the background, taking up loads of memory and CPR cycles.
Test it out and see.
I may just be “Back to My Mac” that is causing mDNSResponder to churn. I turned off “Back to My Mac” in the .Mac preference pane and all is quiet on the mDNSResponder front for me.
@Tom: I don’t have “Back to My Mac” at all. I currently don’t own a .Mac account. I tested this again and it doesn’t seem to work either.
It seems to me that Apple has this process running in the background so that when the option to view them is turned on, the display is instant.
Please run your own tests and get back to me. I used top and Little Snitch to view stats.
Hi! I used your instructions to disable mDNSResponder a couple of days ago and all went fine (the list of local computers in finder was no more). But today a bunch of pc-servers suddenly appeared and I have no idea why? No macs this time and I tried to enable then disable mDNSResponder again but with no luck. any ideas?
Mind Mining Medium ยป Leopard: Turn off Bonjour (mDNSResponder)
Turning off Back to my Mac worked for me as well. It fixed both mDNSResponder and syslogd, which was also out of control.
turning of “Back to my Mac” works with me too, it fixed syslogd and mdnsreponder problem.
Thank the gods. I was sure that something on the university system was sucking my computer dry, but shutting off the “back to my mac” did the trick.
Since we upgraded to OSX 10.5 Leopard on several of the MACs in our department. These machines have been devouring all the the available ports on a Windows Server in our corporate setting. We tried going in a disabling Bonjour and that seems to take care of the problem, however We use Font Suitcase Fusion and that program uses Bonjour to check for other machines with the same copy of the software, so the software will not launch and function without Bonjour. Any ideas or solutions to this problem? Any ideas would be appreciated.
I have been having the same problem with my Leopard systems. Disabling Bonjour did the trick. Thank you!
I’ve not had that problem, but for some reason, on my Leopard system, I was no longer seeing the different computers in my network. Thanks to this page, I now know that Bonjour = mdnsresponder, so a quick trip to Activity Monitor, and a quit & restart process later and everything is working again!
Thanks!
are we talking about disabling bonjour on the server or on the client workstations
Thanks for the tip. Disabling bonjour also fixes an issue with slow dns lookups (2-3 seconds for each and every lookup). This happens when you add the .local domain to list of search domains.
I have just the opposite problem. I would like to turn Bonjour on. Step by step please.
I too would like it turned on. I inadvertently denied access to it when I downloaded a ProTools upgrade. Now my ipp printing doesn’t work! Help!
It’s written in the article…
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.mDNSResponder.plist