host/check-blacklist.sh

   1 #!/bin/sh
   2 if [ $# -lt 2 ]
   3 then
   4         cat << END
   5 Usage $0 <hostname> <blacklist>
   6 Where
   7   hostname      - host to check on blacklist
   8   blacklist     - DNSBL blacklist (e.g. "zen.spamhaus.org")
   9 END
  10         exit 255
  11 fi
  12
  13 ip=$(dig a "$1" +short)
  14 if [ -n "$ip" ]
  15 then
  16         bl=$(dig a "$(printf "%s." "$ip" | tac -s.)$2" +short)
  17         [ -n "$bl" ] && { echo "$ip is blacklisted."; exit 1; } || echo "$ip is not blacklisted."
  18 fi