Jan 142015

frankensteinCurrently there are several articles like the one on Arstechnica that complain about the DNS resolver in OS X 10.10. Amongst others they report issues with name resolution per se and Bonjour machine names that get changed. Many of this posts then suggest to replace the new discoveryd with the legacy mDNSResponder service.

This post acts as a warning: Never ever replace core system components!

By following the instructions to replace discoveryd you are completely on your own. By replacing such a vital system component you can introduce all kinds of bugs. Many of those may not even look related to name resolution but are triggered by some strange side effect. Furthermore I’m pretty sure Apple does not test their updates with this Frankenstein-like system configuration. Last but not least you may even introduce security problems.

Even if there are bugs, which is inevitable, please report them to the developers and wait for a system update to fix them. You simply don’t know what problems you cause by doing otherwise.

  2 Responses to “Never Ever Replace Core System Components”

  1. I was shocked at that article. Also most of his issues are not issues I experience in even the the largest OS X deployments. Great notes here.

    • Hi Trevor,

      Thanks for commenting. It’s great if this workaround is working for you however I still think it’s a very very bad idea to replace system components. It’s just not worth doing so, because it might end in a support nightmare. As I said already you are completely on your own as your system is not supported anymore. If you had a problem with any of my applications I would not give you support as I simply don’t know what side effects you triggered (for example slightly different API responses).

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