Syncookies

DJB's page: http://cr.yp.to/syncookies.html

Issues with DJB's Writeup

• "SYN cookies 'do not allow to use TCP extensions' such as large windows. Reality: SYN cookies don't hurt TCP extensions. A connection saved by SYN cookies can't use large windows; but the same is true without SYN cookies, because the connection would have been destroyed."
  • This is only true for machines expected to suffer SYNflood attacks.
  • The usefulness of TCP Large Window Extensions means I disable SYNcookies on internal machines