blocking IP address sites vs hostname

[alexus <alexus@xxxxxxxxx>]

Hi

What's the best way to 403 any site that people go via IP address
instead of hostname?

if someone goes to http://64.237.55.82/ vs http://alexus.org/

so if someone types in http://alexus.org/ it should work yet if
someone types in http://64.237.55.82 it should not

-- 
http://alexus.org/