Failed to get available update data for 47 projects.

I've been getting this message for better part of a week now. My server administrators assure me that no changes have been made in the communications configuration at the server farm but I am unable to retrieve any update data. Additionally, the back up and migrate module seems unable to send any emails on the completion or failure of a backup (I have verified that the backups are succeeding).

What configuration of a redhat server is required by Drupal for communications purposes? Some patches were applied to the server shortly before this problem appeared so I suspect the issue lies there but without the ability to tell the administrators what to look for, I have no argument to make against their claim that nothing has changed.

Does Drupal look for a specific port when sending emails or other communications? Or use a specific communications protocol which may have been impacted by the patches?

I can't tell you specifically what patches were applied since they haven't told /won't tell me.