#!/bin/sh
if echo $1 | egrep -q "(204\.127\.|172\.20\.3|68\.45\.82)"; then
    # This is a Comcast host that my mail might pass through
    echo NXDOMAIN;
else
    host $1 68.46.144.5 | fgrep NXDOMAIN || echo 127.0.0.2;
fi