We begin by navigating to Firewall | Rules and clicking on the appropriate tab (for example, LAN). We then click on one of the Add buttons to add a rule. When the page loads, set the Action to Block; all other options in the Edit Firewall Rule section can remain the same. In the Destination section, select Single host or alias in the drop-down box and then enter 207.58.150.178 in the adjacent edit box. You can enter a brief description in the Description edit box (for example, Block Apple Insider rule) and then click on Save when done. When the page reloads, click on the Apply Changes button.

The final step is to make sure the rule is placed in the appropriate place; in particular, it should be placed with any Allow LAN to any rules, or it will never be reached. One this is done, if the rule order has been changed, click on the Save button below the table, then click on the Apply Changes button, and the rule should take effect. Users on the LAN net should now be blocked from accessing appleinsider.com. To confirm that this is the case, try accessing the site while the rule is enabled, then disable the rule and see what happens. Be sure to clear your browser cache beforehand to make sure you aren't accessing a cached version of the site.