While browsing for services in my local network with Bonjour, I notice that my MacBook Pro provides the _atc._tcp. service. However I couldn't find a description for such a service from the canonical list of macOS services nor inside the DNS-SD registry.

The question is, what is that service? How to use it?

up vote 2 down vote accepted

The _atc._tcp. service is/was the Shared iTunes Library service.

I'm out and about at the moment, but when I get a chance I will update this answer with some sort of link/source to back this up.


I haven't yet had a chance to have a thorough look for a source, although I did do a quick Google search and found a reference to the _atc._tcp. service at this MacRumors discussion. In it you'll see the 10th comment (by priitv8) states:

For comparison, I've included a screenshot from my Shared iTunes Library service (_atc._tcp.).

Also, it occurred to me that you may want to download Bonjour Browser and see if that sheds any more light on this for you. It's an old app but works well (although I haven't used it in macOS Sierra - not sure what you're using).

As an aside, the list of Bonjour service types used in Mac OS X you linked to is not an exhaustive list. It was only a list of common Bonjour service types used in Mac OS X and hasn't been updated since July 2004.

  • I've been using Bonjour Browser; trying to identify a macOS computer from all others via its bonjour services (but that would be the subject of another question altogether). – adib Apr 3 '17 at 10:48

Your Answer


By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.