rdr/help.txt

Redirect traffic addressed to any host at any port to any IP and port.

  rdr allows you to torward any hostname at any port to any IP at
  any port on your Mac.

    rdr [ <host>:<ip> to <ip>:<port> ]
        [ . | on | off | list | reset | restore ]
        --help
        --version

  Usually, you'll want the <ip>:<port> argument to be 127.0.0.1:<port>,
  so try something like: "rdr domain.com:80 to 127.0.0.1:3005"

  Administrator privileges are required for everything other than the
  list, --help, and --version commands/flags.

  HOW IT WORKS:
    rdr will create and apply /etc/hosts rules to to point the domain
    to your IP, and pfctrl configuration rules to forward your ports.