It uses the 0/32 special alias in a rdr rule, and, from the ipfilter FAQ [http://www.phildev.net/ipf/IPFprob.html#prob17]: I'm using interface/32, 0/0 or 0/32, and it doesn't work! These special aliases do not work in IPF rules, or in IPNat rdr rules. They only work in IPNat's map and bimap rules. Thanks! Artom