dhcp6c.conf.5

.\"	$KAME: dhcp6c.conf.5,v 1.30 2005/05/03 06:54:26 jinmei Exp $
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.Dd June 7, 2024
.Dt DHCP6C.CONF 5
.Os KAME
.\"
.Sh NAME
.Nm dhcp6c.conf
.Nd DHCPv6 client configuration file
.\"
.Sh SYNOPSIS
.Pa /usr/local/etc/dhcp6c.conf
.\"
.Sh DESCRIPTION
The
.Nm
file contains configuration information for KAME's DHCPv6 client,
.Nm dhcp6c .
The configuration file consists of a sequence of statements terminated
by a semi-colon (`;').
Statements are composed of tokens separated by white space,
which can be any combination of blanks,
tabs and newlines.
In some cases a set of statements is combined with a pair of brackets,
which is regarded as a single token.
Lines beginning with
.Ql #
are comments.
.Sh Interface specification
There are some statements that may or have to specify interface.
Interfaces are specified in the form of "name unit", such as
.Ar fxp0
and
.Ar gif1.
.\"
.Sh DHCPv6 options
Some configuration statements take the description of a DHCPv6 option
as an argument.
The followings are the format and description of available DHCPv6
options.
.Bl -tag -width Ds -compact
.It Xo
.Ic domain-name-servers
.Xc
means a Domain Name Server option.
.It Xo
.Ic domain-name
.Xc
means a domain name option.
.It Xo
.Ic ntp-servers
.Xc
means an NTP server option.
As of this writing, the option type for this option is not officially
assigned.
.Nm dhcp6c
will reject this option unless it is explicitly built to accept the option.
.It Xo
.Ic sip-server-address
.Xc
means a SIP Server address option.
.It Xo
.Ic sip-server-domain-name
.Xc
means a SIP server domain name option.
.It Xo
.Ic nis-server-address
.Xc
means a NIS Server address option.
.It Xo
.Ic nis-domain-name
.Xc
means a NIS domain name option.
.It Xo
.Ic nisp-server-address
.Xc
means a NIS+ Server address option.
.It Xo
.Ic nisp-domain-name
.Xc
means a NIS+ domain name option.
.It Xo
.Ic bcmcs-server-address
.Xc
means a BCMCS Server address option.
.It Xo
.Ic bcmcs-server-domain-name
.Xc
means a BCMCS server domain name option.
.It Ic ia-pd Ar ID
means an IA_PD
.Pq Identity Association for Prefix Delegation
option.
.Ar ID
is a decimal number of the IAID
.Pq see below about identity associations .
.It Ic ia-na Ar ID
means an IA_PD
.Pq Identity Association for Non-temporary Addresses
option.
.Ar ID
is a decimal number of the IAID
.Pq see below about identity associations .
.It Ic rapid-commit
means a rapid-commit option.
.It Ic authentication Ar authname
means an authentication option.
.Ar authname
is a string specifying parameters of the authentication protocol.
An
.Ic authentication
statement for
.Ar authname
must be provided.
.El
.\"
.Sh Interface statement
An interface statement specifies configuration parameters on the
interface.
The generic format of an interface statement is as follows:
.Bl -tag -width Ds -compact
.It Xo
.Ic interface Ar interface
{
.Ar substatements
};
.Xc
The followings are possible
.Ar substatements
in an interface statement.
.Bl -tag -width Ds -compact
.It Xo
.Ic send Ar send-options
;
.Xc
This statement specifies DHCPv6 options to be sent to the server(s).
Some options can only appear in particular messages according to the
specification,
in which case the appearance of the options is limited to be compliant
with the specification.
.Pp
.Ar send-options
is a comma-separated list of options,
each of which should be specified as described above.
Multiple
.Ic send
statements can also be specified,
in which case all the specified options will be sent.
.Pp
When
.Ic rapid-commit
is specified,
.Nm dhcp6c
will include a rapid-commit option in solicit messages and wait for
an immediate reply instead of advertisements.
.Pp
When
.Ic ia-pd
is specified,
.Nm dhcp6c
will initiate prefix delegation as a requesting router by 
including an IA_PD option with the specified
.Ar ID
in solicit messages.
.Pp
When
.Ic ia-na
is specified,
.Nm dhcp6c
will initiate stateful address assignment by 
including an IA_NA option with the specified
.Ar ID
in solicit messages.
.Pp
In either case, a corresponding identity association statement
must exist with the same
.Ar ID .
.It Ic request Ar request-options ;
This statement specifies DHCPv6 options to be included in an
option-request option.
.Ar request-options
is a comma-separated list of options,
which can consist of the following options.
.Bl -tag -width Ds -compact
.It Xo
.Ic domain-name-servers
.Xc
requests a list of Domain Name Server addresses.
.It Xo
.Ic domain-name
.Xc
requests a DNS search path.
.It Xo
.Ic ntp-servers
.Xc
requests a list of NTP server addresses.
As of this writing, the option type for this option is not officially
assigned.
.Nm dhcp6c
will reject this option unless it is explicitly built to accept the option.
.It Xo
.Ic sip-server-address
.Xc
requests a list of SIP server addresses.
.It Xo
.Ic sip-domain-name
.Xc
requests a SIP server domain name.
.It Xo
.Ic nis-server-address
.Xc
requests a list of NIS server addresses.
.It Xo
.Ic nis-domain-name
.Xc
requests a NIS domain name.
.It Xo
.Ic nisp-server-address
.Xc
requests a list of NIS+ server addresses.
.It Xo
.Ic nisp-domain-name
.Xc
requests a NIS+ domain name.
.It Xo
.Ic bcmcs-server-address
.Xc
requests a list of BCMCS server addresses.
.It Xo
.Ic bcmcs-domain-name
.Xc
requests a BCMCS domain name.
.It Xo
.Ic refreshtime
.Xc
means an information refresh time option.
This can only be specified when sent with information-request
messages;
.Nm dhcp6c
will ignore this option for other messages.
.El
Multiple
.Ic request
statements can also be specified,
in which case all the specified options will be requested.
.It Ic information-only ;
This statement specifies
.Nm dhcp6c
to only exchange informational configuration parameters with servers.
A list of DNS server addresses is an example of such parameters.
This statement is useful when the client does not need stateful
configuration parameters such as IPv6 addresses or prefixes.
.It Ic script Ar \(dqscript-name\(dq ;
This statement specifies a path to script invoked by
.Nm dhcp6c
on a certain condition including when the daemon receives a reply
message.
.Ar script-name
must be the absolute path from root to the script file, be a regular
file, and be created by the same owner who runs the daemon.
.El
.El
.\"
.Sh Identity association statement
Identity association
.Pq IA
is a key notion of DHCPv6.
An IA is uniquely identified in a client by a pair of IA type and
IA identifier
.Pq IAID .
An IA is associated with configuration information dependent on the IA type.
.Pp
An identity association statement defines a single IA with some
client-side configuration parameters.
Its format is as follows:
.Bl -tag -width Ds -compact
.It Xo
.Ic id-assoc Ar type Op Ar ID
{
.Ar substatements
};
.Xc
.Ar type
is a string for the type of this IA.
The current implementation supports
.Ql Ic na
(non-temporary address allocation)
.Ql Ic pd 
(prefix delegation) for the IA type.
.Ar ID
is a decimal number of IAID.
If omitted, the value 0 will be used by default.
.Ar substatements
is a sequence of statements that specifies configuration parameters
for this IA.
Each statement may or may not be specific to the type of IA.
.Pp
The followings are possible
.Ar substatements
for an IA of type
.Ic na .
.Bl -tag -width Ds -compact
.It Xo
.Ic address Ar ipv6-address pltime Op Ar vltime ;
.Xc
specifies an address and related parameters that the client wants to be
allocated.
Multiple addresses can be specified, each of which is described as a
separate
.Ic address
substatement.
.Nm dhcp6c
will include all the addresses
.Pq and related parameters
in Solicit messages,
as an IA_NA prefix option encapsulated in the corresponding IA_NA
option.
Note, however, that the server may or may not respect the specified
prefix parameters.
For parameters of the
.Ic address
substatement,
see
.\" XXX apparently not
.Xr dhcp6s.conf 5 .
.El
.Pp
The followings are possible
.Ar substatements
for an IA of type
.Ic pd .
.Bl -tag -width Ds -compact
.It Xo
.Ar prefix_interface_statement
.Xc
specifies the client's local configuration of how delegated prefixes
should be used
.Pq see below .
.It Ic prefix Ar ipv6-prefix pltime Op Ar vltime ;
specifies a prefix and related parameters that the client wants to be
delegated.
Multiple prefixes can be specified, each of which is described as a
separate
.Ic prefix
substatement.
.Nm dhcp6c
will include all the prefixes
.Pq and related parameters
in Solicit messages,
as an IA_PD prefix option encapsulated in the corresponding IA_PD
option.
Note, however, that the server may or may not respect the specified
prefix parameters.
For parameters of the
.Ic prefix
substatement,
see
.\" XXX apparently not
.Xr dhcp6s.conf 5 .
.El
.El
.\"
.Sh Prefix interface statement
A prefix interface statement specifies configuration parameters of
prefixes on local interfaces that are derived from delegated prefixes.
A prefix interface statement can only appear as a substatement of
an identity association statement with the type
.Ic pd .
The generic format of an interface statement is as follows:
.Bl -tag -width Ds -compact
.It Xo
.Ic prefix-interface Ar interface
{
.Ar substatements
};
.Xc
When an IPv6 prefix is delegated from a DHCPv6 server,
.Nm dhcp6c
will assign a prefix on the
.Ar interface
unless the interface receives the DHCPv6 message that contains the prefix
with the delegated prefix and the parameters provided in
.Ar substatements .
Possible substatements are as follows:
.Bl -tag -width Ds -compact
.It Ic sla-id Ar ID ;
This statement specifies the identifier value of the site-level aggregator
.Pq SLA
on the interface.
.Ar ID
must be a decimal integer which fits in the length of SLA IDs
.Pq see below .
For example,
if
.Ar ID
is 1 and the client is delegated an IPv6 prefix 2001:db8:ffff::/48,
.Nm dhcp6c
will combine the two values into a single IPv6 prefix,
2001:db8:ffff:1::/64,
and will configure the prefix on the specified
.Ar interface .
.It Ic sla-len Ar length ;
.Xc
This statement specifies the length of the SLA ID in bits.
.Ar length
must be a decimal number between 0 and 128.
If the length is not specified by this statement,
the default value 16 will be used.
.It Ic ifid Ar ID ;
This statement specifies the interface identifier value.
.Ar ID
shall be a decimal integer.
It will be combined with the delegated prefix and the
.Ic sla-id
to form a complete interface address.
If the special value
.Ar random
is given, it instructs the client to generate a pseudo random value
during configuration parsing.
If the special value
.Ar eui-64
is given, only the EUI-64 address generation will be attempted which
reflects the historic client behaviour.
When this option is omitted,
.Ar eui-64
will be used, and if it fails the client will fall back to
.Ar random
to allow operation for interfaces without a hardware address.
.El
.El
.\"
.Sh Authentication statement
An authentication statement defines a set of authentication parameters
used in DHCPv6 exchanges with the server(s).
The format of an authentication statement is as follows:
.Bl -tag -width Ds -compact
.It Xo
.Ic authentication Ar authname
{
.Ar substatements
};
.Xc
.Ar authname
is a string which is unique among all authentication statements in the
configuration file.
It will specify a particular set of authentication parameters when
.Ic authentication
option is specified in the
.Ic interface
statement.
Possible substatements of the
.Ic authentication
statement are as follows:
.Bl -tag -width Ds -compact
.It Xo
.Ic protocol Ar authprotocol
;
.Xc
specifies the authentication protocol.
Currently, the only available protocol as
.Ar authprotocol
is
.Ic delayed ,
which means the DHCPv6 delayed authentication protocol.
.It Xo
.Ic algorithm Ar authalgorithm
;
.Xc
specifies the algorithm for this authentication.
Currently, the only available algorithm is HMAC-MD5,
which can be specified as one of the followings:
.Ic hmac-md5 ,
.Ic HMAC-MD5 ,
.Ic hmacmd5 ,
or
.Ic HMACMD5 .
This substatement can be omitted.
In this case,
HMAC-MD5 will be used as the algorithm.
.It Xo
.Ic rdm Ar replay-detection-method
;
.Xc
specifies the replay protection method for this authentication.
Currently, the only available method is
.Ic monocounter ,
which means the use of a monotonically increasing counter.
If this method is specified,
.Ic dhcp6c
will use an NTP-format timestamp when it authenticates the message.
This substatement can be omitted,
in which case
.Ic monocounter
will be used as the method.
.El
.El
.\"
.Sh Keyinfo statement
A keyinfo statement defines a secret key shared with the server(s)
to authenticate DHCPv6 messages.
The format of a keyinfo statement is as follows:
.Bl -tag -width Ds -compact
.It Xo
.Ic keyinfo Ar keyname
{
.Ar substatements
};
.Xc
.Ar keyname
is an arbitrary string.
It does not affect client's behavior but is provided for readability
of log messages.
Possible substatements of the
.Ic keyinfo
statement are as follows:
.Bl -tag -width Ds -compact
.It Xo
.Ic realm Ar \(dqrealmname\(dq
;
.Xc
specifies the DHCP realm.
.Ar realmname
is an arbitrary string,
but is typically expected to be a domain name like \(dqkame.net\(dq .
.It Xo
.Ic keyid Ar ID
;
.Xc
specifies the key identifier,
.Ar ID ,
as a decimal number.
A secret key is uniquely identified within the client by the DHCP
realm and the key identifier.
.It Xo
.Ic secret Ar \(dqsecret-value\(dq
;
.Xc
specifies the shared secret of this key.
.Ar \(dqsecret-value\(dq
is a base-64 encoded string of the secret.
.It Xo
.Ic expire Ar \(dqexpiration-time\(dq
;
.Xc
specifies the expiration time of this key.
.Ar \(dqexpiration-time\(dq
should be formatted in one of the followings:
.Ar yyyy-mm-dd HH:MM ,
.Ar mm-dd HH:MM ,
or
.Ar HH:MM ,
where
.Ar yyyy
is the year with century (e.g., 2004),
.Ar mm
is the month,
.Ar dd
is the day of the month,
.Ar HH
is the hour of 24-hour clock,
and
.Ar MM
is the minute,
each of which is given as a decimal number.
Additionally,
a special keyword
.Ic forever
can be specified as
.Ar expiration-time ,
which means the key has an infinite lifetime and never expires.
This substatement can be omitted,
in which case
.Ic forever
will be used by default.
.El
.El
.\"
.Sh Examples
The followings are a sample configuration to be delegated an IPv6
prefix from an upstream service provider.
With this configuration
.Nm dhcp6c
will send solicit messages containing an IA_PD option,
with an IAID 0,
on to an upstream PPP link,
.Ar ppp0 .
After receiving some prefixes from a server,
.Nm dhcp6c
will then configure derived IPv6 prefixes with the SLA ID 1 on a
local ethernet interface,
.Ar ne0 .
Note that the IAID for the
.Ic id-assoc
statement is 0 according to the default.
.Bd -literal -offset
interface ppp0 {
        send ia-pd 0;
};

id-assoc pd {
	prefix-interface ne0 {
		sla-id 1;
	};
};
.Ed
.Pp
If a shared secret should be configured in both the client and the
server for DHCPv6 authentication,
it would be specified in the configuration file as follows:
.Bd -literal -offset
keyinfo kame-key {
        realm "kame.net";
        keyid 1;
        secret "5pvW2g48OHPvkYMJSw0vZA==";
};
.Ed
.Pp
One easy way of generating a new secret in the base64 format is to
execute the
.Xr openssl 1
command (when available) as follows,
.Bd -literal -offset
% openssl rand -base64 16
.Ed
.Pp
and copy the output to the
.Nm dhcp6c.conf
file.
.Pp
To include an authentication option for DHCPv6 authentication,
the
.Ic interface
statement should be modified and an
.Ic authentication
statement should be added as follows:
.Bd -literal -offset
interface ppp0 {
        send ia-pd 0;
        send authentication kame;
};

authentication kame {
	protocol delayed;
};
.Ed
.Pp
.Bd -literal -offset
interface fxp0 {
        send ia-na 0;
};
.Ed
.Sh SEE ALSO
.Xr dhcp6c 8
.\"
.Sh HISTORY
The
.Nm
configuration file first appeared in the WIDE/KAME IPv6 protocol
stack kit.