Ubuntu Manpage: isatapd - ISATAP client for Linux

NAME

       isatapd - ISATAP client for Linux

SYNOPSIS

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

DESCRIPTION

       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

OPTIONS

-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 daemon.

--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

--version
print version

EXIT STATUS

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

SIGNALS

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

       SIGINT SIGTERM
              Gracefully shut down tunnel device and terminate.

SYSLOG

       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.

NOTES

       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.

AUTHORS

       Sascha Hlusiak <mail@saschahlusiak.de>

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

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