Eyes in the Back of Your Head (General)

Your superior battle sense helps minimize the threat of flanking attacks.

(Complete Warrior, p. 98)  
Originally posted on D&D tools

• Prerequisite Wisdom 13, base attack bonus +1,
• Benefit Attackers do not gain the usual +2 bonus on their attack rolls when flanking you. This feat grants no effect whenever you are attacked without benefit of your Dexterity modifier to Armor Class, such as when you are flat-footed. You may still be sneak attacked when flanked.
• Normal When you are flanked, the flanking opponents receive a +2 bonus on their attack rolls against you.