Provided by: isatapd_0.9.7-5_amd64 bug


       isatapd - ISATAP client for Linux


       isatapd --help
       isatapd [ --daemon ] [ --link device ] [ options ] [ router ] [ ... ]


       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  potential  router  list  ,  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


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

       -l --link device
              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 --mtu bytes
              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 --ttl hoplimit
              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 --router router
              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 --interval seconds
              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-dns seconds
              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 --pid file
              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

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

              Default: nobody

       -v --verbose
              increase verbosity

       -q --quiet
              decrease verbosity

       -h --help
              print usage

              print version


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


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

              Gracefully shut down tunnel device and terminate.


       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.


       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.


       Sascha Hlusiak <>

       Kwong-Sang Yin <>

       Fred Templin <>


       ip(8) syslog-ng(8)