Within the dashboard/sitewide settings/access page at the bottom is "IP Address Blocker". I've found the field to add IP Addresses. However, when I copy/paste IP Addresses into this field and "save" i get an error -
Warning: Cannot modify header information - headers already sent by (output started at /home1/absolvc8/public_html/concrete/controllers/dashboard/settings/controller.php:229) in /home1/absolvc8/public_html/concrete/libraries/controller.php on line 277

It obviously isn't working as the IP Addresses I'm trying to block keep showing up. Seems pretty straight forward but I'm at a loss right now.