miredo - Teredo IPv6 tunneling for Unix

       Rémi Denis-Courmont <remi at remlab dot net>

       http://www.remlab.net/miredo/

miredo                                            February 2008                                        MIREDO(8)

Miredo  is a daemon program providing a Teredo tunnel service compatible with the "Teredo: Tunneling IPv6
       over UDP through NATs" Internet proposed standard (RFC 4380). It can  provide  either  Teredo  client  or
       Teredo relay functionality.

       This is mostly useful to provide IPv6 connectivity to users behind NAT, most of which do not support IPv6
       at  all.  Many  NATs  do  not even support proto-41 forwarding, so it is not possible to set up a 6to4 or
       point-to-point IPv6-over-IPv4 tunnel through them.

       A Teredo relay is an IPv6 router which forwards IPv6 packets between the IPv6 Internet and Teredo clients
       by encapsulating these IPv6 packets over UDP/IPv4.

       A Teredo client is an IPv6-enabled host which is located behind an IPv4-only Network  Address  Translator
       (a.k.a. NAT), and encapsulates its IPv6 traffic inside UDP over IPv4 packets.

       A  Teredo  server  is  a  special  Teredo  relay which is required for Teredo clients to setup their IPv6
       connectivity through Teredo. A Teredo server must have to global static  subsequent  IPv4  addresses.  It
       receives packets from Teredo clients and Teredo relays on UDP port 3544.

/etc/miredo/miredo.conf
              The default configuration file.

       /var/run/miredo.pid
              The process-id file.

       miredo - Teredo IPv6 tunneling for Unix

-cconfig_file or --configconfig_file
              Specify    an    alternate    configuration    file   for   Miredo   instead   of   the   default,
              /etc/miredo/miredo.conf.

       -f or --foreground
              Do not detach from the console. Run the program in the foreground.

       -h or --help
              Display some help and exit.

       -t or --chrootdir
              Specify a directory to use as a root after initialization is completed.  When  used  as  a  Teredo
              client,  the  hostname  resolver  library  files  must be present in the chroot. The directory can
              safely be left empty for a Teredo relay.

       -uusername or --userusername
              Override the user that the program will run as. By default, it runs as nobody.

       -V or --version
              Display program version and license and exit.

       server_name
              This  optional  command  argument  specifies  a  Teredo  server  to  use.  It  will  override  any
              ServerAddress  directive found in the configuration file. It is ignored if RelayType is not set to
              "client" (see miredo.conf).

Miredo requires root privileges to create its  IPv6  tunneling  network  interface,  and  to  set  it  up
       properly.  Once  its  initialization  is  complete,  it  will  setgid, chroot into an empty directory and
       ultimately setuid (see option -u), so as to decrease the system's exposure to potential security  issues.
       However, if Miredo runs as a Teredo client, it needs root privileges when running, in order to change the
       tunneling  network  interface  settings  automatically.  To  prevent  possible  root  compromise,  Miredo
       implements privelegesseparation. The process that handles data from the network is not privileged.

       While that is not specific to nor dependent on Miredo, it should be noted that Teredo connectivity allows
       anyone behind a NAT to obtain global public IPv6 connectivity. It might break some corporate policy.   If
       that  is  an  issue,  outgoing  UDP packets with destination port 3544 should be blocked at the perimeter
       firewall.

miredo.conf(5), miredo-server(8), ipv6(7), route(8), ip(8)

SIGHUP Force a reload of the daemon.

       SIGINT, SIGTERM Shutdown the daemon.

       SIGUSR1, SIGUSR2 Do nothing, might be used in future versions.

miredo [-cconfig_file] [-f] [-uuser] [ -tchrootdir] [server_name]