iankelling.org Git - distro-setup/blob - vpn-mail-forward

   1 #!/bin/bash
   2
   3 set -eE -o pipefail
   4 trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR
   5 m() { printf "%s\n" "$*";  "$@"; }
   6 gw=$(/usr/sbin/ip route | sed -rn 's/^default via .* dev (\S+).*/\1/p')
   7 do-forward() {
   8     cmd=$1; shift
   9     for port; do
  10         m /sbin/iptables -t nat $cmd PREROUTING -i $gw -p tcp -m tcp --dport $port -j DNAT --to-destination 10.8.0.4:$port
  11         # we could leave these on all the time but its convenient to do it here
  12     done
  13     m /sbin/iptables $cmd FORWARD -i tun+ -o $gw -j ACCEPT
  14     m /sbin/iptables $cmd FORWARD -i $gw -o tun+ -j ACCEPT
  15 }
  16
  17 ports=(25 143 587)
  18 case $1 in
  19     start)
  20         do-forward -A ${ports[@]}
  21         ;;
  22     stop)
  23         do-forward -D ${ports[@]}
  24         ;;
  25     *)
  26         echo "$0: error: expected 1 argument of start or stop"
  27         exit 1
  28         ;;
  29 esac