Jimmy commented: #The underlying problem is that "BCP38" is not really a "best common practice", #despite the name of the series. # #It's really a "Best Uncommon Practice that really ought to be more common", #but we can't control operators and force them to make it more common. # #Lots of networks don't and will not ever implement BCP38; BCP38 is not being #more widely implemented, and there's no obvious action that will #force it to change. Check out the MIT Spoofer Project (http://spoofer.csail.mit.edu/summary.php) BCP38 anti-spoofing filtering is more common than you might think (on the order of 80% of {netblocks, IPs, ASNs} filter as of October 2011) Regards, Joe