since a few version updates (I don't remember exactly, I'm using 2.1.2 now) outgoing trackbacks don't get processed anymore.
I did some research and found that the cron field in wp_options table contains lots of (unprocessed?) do_pings() requests (field size is now ~12kB text).
Ingo Putzlowitsch (who has the same problem) recommended me in the german support forum to call do_ping() manually. I wrote a php script
<?php require_once( dirname(__FILE__) . '/wp-config.php'); require_once( dirname(__FILE__) . '/wp-includes/functions.php'); do_all_pings(); ?>
When calling that script do_pings.php via its URL I get after about 25 seconds
Premature end of script headers: do_pings.php
If it would run, it would at least help a little and cure the symptoms. Why the cron doesn't run I don't know.
BTW: I have a testblog running on the same server where cron gets processed regularly and trackbacks get sent.
Incoming trackbacks/pings work on both.
What can I do, how can I test? I only have access to the access logs, not to the error or php logs.