There are a few automatic connections made to Mozilla servers by products distributed by Mozilla.
The are mentioned in the privacy policy:
<a href="http://www.mozilla.com/en-US/legal/privacy/firefox-en.html" rel="nofollow">http://www.mozilla.com/en-US/legal/privacy/firefox-en.html</a><p>And there is a support article with instructions on disabling them:
<a href="http://support.mozilla.com/en-US/kb/Firefox+makes+unrequested+connections#Auto_update_checking" rel="nofollow">http://support.mozilla.com/en-US/kb/Firefox+makes+unrequeste...</a><p>Note that these "pings" aren't implemented as "phone home" type tracking.  Rather, they are necessary parts of useful features such as automatic update tracking and extension blocklisting.