trouble with connection to rsync.php.net

Hi all, I'm the maintainer of tw.php.net mirror site. Recently, we have trouble with rsync connection to rsync.php.net. From tw.php.net, we can reach port 873 of rsync.php.net, but when running rsync, it times out when getting the file lists. I suspect that it is caused by intrusion prevention system here. But before checking that, I just want to make sure rsync.php.net does not block us out. If rsync.php.net does block us, please give me the reasons. Thanks, Rong-En Fan