isatapd - ISATAP client for Linux

       Sascha Hlusiak <mail@saschahlusiak.de>

       Kwong-Sang Yin <kwong-sang.yin@boeing.com>

       Fred Templin <fred.l.templin@boeing.com>

isatapd  is a userspace program or daemon that sets up and maintains an ISATAP client tunnel by using the
       kernels ISATAP capabilities, first introduced with 2.6.25.

       The program will create the tunnel, periodically query the specified routers, add them to  the  potentialrouterlist  ,  send periodic router solicitations and parse router advertisements.  isatapd will try to
       keep the tunnel up and running, even if the network topology changes.

       See NOTES below for more information

       On success zero is returned, otherwise a non-zero value is returned.

       isatapd - ISATAP client for Linux

       Network data will be processed by isatapd with privileges of an unprivileged user to minimize  impact  of
       bugs in the networking code. To create and maintain the tunnel device, root privileges are necessary.

       Whenever the tunnel link interface goes down or the source address for the local tunnel endpoint changes,
       the  tunnel device will be destroyed and recreated, if possible. Note that till then your tunnel might be
       in a unusable state.

-n--namename
              Name of the tunnel interface. Default is is0.

       -l--linkdevice
              Tunnel link device. If specified, tunnel will be restricted  to  that  device,  allowing  multiple
              instances  of isatapd with different tunnels. The tunnel can only exist as long as the link device
              is up and has a IPv4 address configured.

              If unspecified or 'auto' , the outgoing IPv4 address will be guessed for the first router and  the
              tunnel  created  accordingly.  The  tunnel  device  will only created, if there is a possible IPv4
              source address to reach the first router.

       -m--mtubytes
              Sets the MTU to bytes for the tunnel device, minimum is 1280. If unspecified,  'auto'  or  0,  the
              kernel will choose the MTU, usually 1480.

       -t--ttlhoplimit
              Set  the  tunnel  hoplimit,  default  is  64.  Specifying 'auto' or 'inherit' will make the tunnel
              inherit the ttl from the linked device.

       -N--nopmtudisc
              Disable (IPv4) Path MTU Discovery on this tunnel. For this to work --ttl has to be set to inherit.
              Default: do Path MTU Discovery to reduce redundant fragmentation.

       -r--routerrouter
              Set a potential router.  isatapd will resolv the hostname, add the IPv4 address  to  the  PRL  and
              send  periodic  router  solicitation  messages.  Up  to 10 potential routers can be specified, the
              default is the unqualified domainname "isatap".

       -i--intervalseconds
              Default interval to send router solicitations. If the router lifetime  is  lower  or  interval  is
              'auto' , the interval will be 80 of the router's lifetime. Can be used to force solicitations at a
              shorter interval.

              Default: auto-D--check-dnsseconds
              Interval  to  perform  DNS resolution of configured routers and to recreate the PRL, if necessary.
              Set to 0 to disable.

              Default: 3600 sec = 1 hour

       -d--daemon
              fork to background. No logging is available yet.

       -p--pidfile
              Store the pid as plaintext to file. The pid file will be write-locked to prevent multiple  running
              instances. Useful for scripts and when running isatapd as a daemon.

       --userusername
              Drop privileges to this user when running the solicitation loop.

              Default: nobody-v--verbose
              increase verbosity

       -q--quiet
              decrease verbosity

       -h--help
              print usage

       --version
              print version

ip(8) syslog-ng(8)

       http://www.ietf.org/rfc/rfc5214.txt

isatapd-0.9.7                                 September 13th, 2013                                    isatapd(8)

SIGHUP Force sending router solicitations and recreate the tunnel, if neccessary.

       SIGINTSIGTERM
              Gracefully shut down tunnel device and terminate.

isatapd--helpisatapd [ --daemon ] [ --linkdevice ] [ options ] [ router ] [ ... ]

isatapd  logs to stderr when run in foreground and to syslog(3), using the facility LOG_DAEMON. Verbosity
       can be controlled with the -v and -q switches.