dhcp6c.8

.\"	$KAME: dhcp6c.8,v 1.36 2005/03/17 05:27:01 suz Exp $
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.Dd June 7, 2024
.Dt DHCP6C 8
.Os KAME
.Sh NAME
.Nm dhcp6c
.Nd DHCPv6 client daemon
.\"
.Sh SYNOPSIS
.Nm
.Op Fl c Ar configfile
.Op Fl Ddfint
.Op Fl p Ar pid-file
.Op Ar interfaces...
.\"
.Sh DESCRIPTION
.Nm
works as a DHCPv6 client and gets information from DHCPv6 servers
to configure the specified
.Ar interface .
Multiple
.Ar interfaces
can be specified separated by spaces or tabs,
in which case
.Nm
will work on all the interfaces simultaneously.
.Pp
The command line options are:
.Bl -tag -width indent
.\"
.It Fl c Ar configfile
Use
.Ar configfile
as the configuration file.
.It Fl d
Print debugging messages.
.It Fl D
Even more debugging information is printed.
.It Fl f
Foreground mode (useful when debugging).
Although
.Nm
usually prints warning, debugging, or error messages to
.Xr syslog 8 ,
it prints the messages to standard error if this option is
specified.
.It Fl i
Info-req mode.
In this mode, stateless DHCPv6 is executed with the following configuration,
and the obtained info is written to stdout.
After this output,
.Nm
is terminated.  (suits for a use in shell-script etc).
.Bd -literal -offset
 interface (interface given in the argument) {
	information-only;
	script (a script which displays the received information to stdout);
 };
.Ed
.Pp
Since the configuration is internally generated, you cannot provide a configuration in this mode.  If you want to have different actions for the stateless DHCPv6 information, you should write an appropriate configuration and invoke
.Nm
without this option.
.It Fl n
Prevent Release message from being sent to DHCPv6 server when
.Nm
stops.
This is useful for preventing a new address from being configured by
the DHCPv6 server when restarting the DHCPv6 client.
.It Fl p Ar pid-file
Use
.Ar pid-file
to dump the process ID of
.Nm .
.It Fl t
Only parse the configuration and exit.
.El
.Pp
The program will daemonize itself on invocation unless the
.Fl f ,
.Fl i ,
or
.Fl t
option is specified.
.Pp
Upon receipt of a
.Dv SIGHUP ,
.Dv SIGINT ,
.Dv SIGTERM ,
or
.Dv SIGUSR1
signal,
.Nm
will remove all stateful resources from the system.
After that,
.Dv SIGHUP
reinitializes the daemon,
and both
.DV SIGINT
or
.Dv SIGTERM
stop the daemon.
In these cases,
DHCPv6 Release message will be sent to release resources
assigned from servers.
.Dv SIGUSR1
stops the daemon as
.Dv SIGINT
or
.Dv SIGTERM
does though DHCPv6 Release message will not be sent.
.\"
.Sh FILES
.Bl -tag -width /usr/local/etc/dhcp6c.conf -compact
.It Pa /var/run/dhcp6c.pid
is the default file that contains pid of the currently running
.Nm dhcp6c .
.It Pa /usr/local/etc/dhcp6c.conf
is the default configuration file.
.It Pa /var/db/dhcp6c_duid
is the file to store the client's DUID.
.El
.Sh Configuration Script
When
.Nm
receives a reply message,
it will invoke a supplementary configuration script specified in the
.Xr dhcp6c.conf 5
file.
The daemon will provide the script with configuration parameters as
environment variables,
which include:
.Pp
.Bl -tag -width Ds -compact
.It Li PDINFO
The delegated prefix for the interface.
Make sure to use a separate script for each interface when using
multiple interfaces at once.
.It Li REASON
The reason why the script is invoked.
One of the following values is set based on a message
which the client sent before the
.Li REPLY
message arrives:
.Bl -tag -width "INFOREQ" -compact -offset indent
.It Li INFOREQ
The client sent an
.Li INFORMATION REQUEST
message.
.It Li REQUEST
The client sent a
.Li REQUEST
message.
.It Li RENEW
The client sent a
.Li RENEW
message.
.It Li REBIND
The client sent a
.Li REBIND
message.
.It Li RELEASE
The client sent a
.Li RELEASE
message.
.It Li EXIT
This happens when
.Nm
exits.
.El
.It Ic new_domain_name_servers
A list of available DNS servers,
each of which is an IPv6 numeric address and is separated by a white
space character.
.It Ic new_domain_name
A list of DNS names,
which provides DNS name search path.
.It Ic new_ntp_servers
A list of available NTP servers,
each of which is an IPv6 numeric address and is separated by a white
space character.
.It Ic new_sip_servers
A list of available SIP server addresses,
each of which is an IPv6 numeric address and is separated by a white
space character.
.It Ic new_sip_name
A list of SIP server domain names.
.It Ic new_nis_servers
A list of available NIS server addresses,
each of which is an IPv6 numeric address and is separated by a white
space character.
.It Ic new_nis_name
A list of NIS domain names.
.It Ic new_nisp_servers
A list of available NIS+ server addresses,
each of which is an IPv6 numeric address and is separated by a white
space character.
.It Ic new_nisp_name
A list of NIS+ domain names.
.It Ic new_bcmcs_servers
A list of available BCMCS server addresses,
each of which is an IPv6 numeric address and is separated by a white
space character.
.It Ic new_bcmcs_name
A list of BCMCS server domain names.
.El
.Pp
Note that the daemon does not always provide all the parameters.
It sets an environment variable only when the corresponding
configuration parameter is provided by the DHCPv6 server.
.\"
.Sh SEE ALSO
.Xr daemon 3 ,
.Xr dhcp6c.conf 5 .
.Rs
.%A Ralph Droms, Editor
.%D 2003
.%T Dynamic Host Configuration Protocol for IPv6 (DHCPv6)
.%R RFC 3315
.Re
.\"
.Sh HISTORY
The
.Nm
command first appeared in WIDE/KAME IPv6 protocol stack kit.
.\"
.Sh BUGS
.Nm
is incomplete and violates DHCPv6 protocol spec, in several aspects.
In particular, temporary address assignment is intentionally omitted.
.Pp
Information Refresh Time Option is not recognied in Info-req mode, since
.Nm
terminates after it receives a REPLY message.