CURL broken in CentOS 7 / RHEL7 for past year
If you suspected maybe WordPress and other PHP apps were slower to ping/trackback sites and other fetches under CentOS 7 than CentOS 6, you aren’t imagining things.
Apparently libCurl (and therefore Curl in PHP) has been broken for over a year now without RedHat applying the available patch and pushing an update.
https://bugs.centos.org/view.php?id=8076
https://bugzilla.redhat.com/show_bug.cgi?id=1130239
patch: https://github.com/bagder/curl/commit/d529f388 (note July 2013)