NAME¶
dhcp6c.conf —
DHCPv6 client
configuration file
SYNOPSIS¶
/etc/wide-dhcpv6/dhcp6c.conf
DESCRIPTION¶
The
dhcp6c.conf file contains configuration information for
KAME's DHCPv6 client,
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 ‘
#
’ are comments.
Interface specification¶
There are some statements that may or have to specify interface. Interfaces are
specified in the form of "name unit", such as
fxp0 and
gif1.
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.
- domain-name-servers
- means a Domain Name Server option.
- domain-name
- means a domain name option.
- ntp-servers
- means an NTP server option. As of this writing, the option
type for this option is not officially assigned. dhcp6c
will reject this option unless it is explicitly built to accept the
option.
- sip-server-address
- means a SIP Server address option.
- sip-server-domain-name
- means a SIP server domain name option.
- nis-server-address
- means a NIS Server address option.
- nis-domain-name
- means a NIS domain name option.
- nisp-server-address
- means a NIS+ Server address option.
- nisp-domain-name
- means a NIS+ domain name option.
- bcmcs-server-address
- means a BCMCS Server address option.
- bcmcs-server-domain-name
- means a BCMCS server domain name option.
- ia-pd
ID
- means an IA_PD (Identity Association for Prefix Delegation)
option. ID is a decimal number of the IAID (see
below about identity associations).
- ia-na
ID
- means an IA_PD (Identity Association for Non-temporary
Addresses) option. ID is a decimal number of the
IAID (see below about identity associations).
- rapid-commit
- means a rapid-commit option.
- authentication
authname
- means an authentication option.
authname is a string specifying parameters of the
authentication protocol. An authentication statement for
authname must be provided.
Interface statement¶
An interface statement specifies configuration parameters on the interface. The
generic format of an interface statement is as follows:
- interface
interface { substatements
};
- The followings are possible
substatements in an interface statement.
- send
send-options ;
- 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.
send-options is a comma-separated list of options,
each of which should be specified as described above. Multiple
send statements can also be specified, in which case
all the specified options will be sent.
When rapid-commit is specified,
dhcp6c will include a rapid-commit option in solicit
messages and wait for an immediate reply instead of advertisements.
When ia-pd is specified, dhcp6c will
initiate prefix delegation as a requesting router by including an
IA_PD option with the specified ID in solicit
messages.
When ia-na is specified, dhcp6c will
initiate stateful address assignment by including an IA_NA option with
the specified ID in solicit messages.
In either case, a corresponding identity association statement must
exist with the same ID.
- request
request-options;
- This statement specifies DHCPv6 options to be included
in an option-request option. request-options is
a comma-separated list of options, which can consist of the following
options.
- domain-name-servers
- requests a list of Domain Name Server
addresses.
- domain-name
- requests a DNS search path.
- ntp-servers
- requests a list of NTP server addresses. As of this
writing, the option type for this option is not officially
assigned. dhcp6c will reject this option unless
it is explicitly built to accept the option.
- sip-server-address
- requests a list of SIP server addresses.
- sip-domain-name
- requests a SIP server domain name.
- nis-server-address
- requests a list of NIS server addresses.
- nis-domain-name
- requests a NIS domain name.
- nisp-server-address
- requests a list of NIS+ server addresses.
- nisp-domain-name
- requests a NIS+ domain name.
- bcmcs-server-address
- requests a list of BCMCS server addresses.
- bcmcs-domain-name
- requests a BCMCS domain name.
- refreshtime
- means an information refresh time option. This can
only be specified when sent with information-request messages;
dhcp6c will ignore this option for other
messages.
Multiple request statements can also be specified, in
which case all the specified options will be requested.
- information-only;
- This statement specifies 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.
- script
"script-name";
- This statement specifies a path to script invoked by
dhcp6c on a certain condition including when the
daemon receives a reply message. 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.
Profile statement¶
Some setups may require to configure an interface independently from its name.
Profiles are available for this particular purpose. They follow the same
syntax as an interface statement except they can be arbitrarily named. It is
then possible to choose which profile to use for a given interface on the
command line.
Identity association
statement¶
Identity association (IA) is a key notion of DHCPv6. An IA is uniquely
identified in a client by a pair of IA type and IA identifier (IAID). An IA is
associated with configuration information dependent on the IA type.
An identity association statement defines a single IA with some client-side
configuration parameters. Its format is as follows:
- id-assoc
type
[ID] {
substatements };
- type is a string for the type of this
IA. The current implementation supports
‘
na
’ (non-temporary
address allocation)
‘pd
’ (prefix
delegation) for the IA type. ID is a decimal number
of IAID. If omitted, the value 0 will be used by default.
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.
The followings are possible substatements for an IA of
type na.
- address
ipv6-address pltime
[vltime];
- 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 address
substatement. dhcp6c will include all the addresses
(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 address
substatement, see dhcp6s.conf(5).
The followings are possible substatements for an IA of
type pd.
- prefix_interface_statement
- specifies the client's local configuration of how
delegated prefixes should be used (see below).
- prefix
ipv6-prefix pltime
[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 prefix
substatement. dhcp6c will include all the prefixes
(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 prefix
substatement, see dhcp6s.conf(5).
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
pd. The generic format of an
interface statement is as follows:
- prefix-interface
interface { substatements
};
- When an IPv6 prefix is delegated from a DHCPv6 server,
dhcp6c will assign a prefix on the
interface unless the interface receives the DHCPv6
message that contains the prefix with the delegated prefix and the
parameters provided in substatements. Possible
substatements are as follows:
- sla-id
ID ;
- This statement specifies the identifier value of the
site-level aggregator (SLA) on the interface. ID
must be a decimal integer which fits in the length of SLA IDs (see
below). For example, if ID is 1 and the client
is delegated an IPv6 prefix 2001:db8:ffff::/48,
dhcp6c will combine the two values into a single
IPv6 prefix, 2001:db8:ffff:1::/64, and will configure the prefix on
the specified interface.
- sla-len
length ;
- This statement specifies the length of the SLA ID in
bits. 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.
- ifid
ID ;
- This statement specifies the interface id.
ID must be a decimal integer. It will be
combined with the delegated prefix and the sla-id to form a complete
interface address. The default is to use the EUI-64 address of the
interface.
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:
- authentication
authname { substatements };
- 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
authentication option is specified in the
interface statement. Possible substatements of the
authentication statement are as follows:
- protocol
authprotocol ;
- specifies the authentication protocol. Currently, the
only available protocol as authprotocol is
delayed, which means the DHCPv6 delayed
authentication protocol.
- algorithm
authalgorithm ;
- specifies the algorithm for this authentication.
Currently, the only available algorithm is HMAC-MD5, which can be
specified as one of the followings: hmac-md5,
HMAC-MD5, hmacmd5, or
HMACMD5. This substatement can be omitted. In this
case, HMAC-MD5 will be used as the algorithm.
- rdm
replay-detection-method ;
- specifies the replay protection method for this
authentication. Currently, the only available method is
monocounter, which means the use of a monotonically
increasing counter. If this method is specified,
dhcp6c will use an NTP-format timestamp when it
authenticates the message. This substatement can be omitted, in which
case monocounter will be used as the method.
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:
- keyinfo
keyname { substatements };
- keyname is an arbitrary string. It
does not affect client's behavior but is provided for readability of log
messages. Possible substatements of the keyinfo
statement are as follows:
- realm
"realmname" ;
- specifies the DHCP realm.
realmname is an arbitrary string, but is
typically expected to be a domain name like "kame.net"
.
- keyid
ID ;
- specifies the key identifier, ID,
as a decimal number. A secret key is uniquely identified within the
client by the DHCP realm and the key identifier.
- secret
"secret-value" ;
- specifies the shared secret of this key.
"secret-value" is a base-64 encoded
string of the secret.
- expire
"expiration-time" ;
- specifies the expiration time of this key.
"expiration-time" should be formatted
in one of the followings: yyyy-mm-dd HH:MM,
mm-dd HH:MM, or HH:MM,
where yyyy is the year with century (e.g.,
2004), mm is the month, dd
is the day of the month, HH is the hour of
24-hour clock, and MM is the minute, each of
which is given as a decimal number. Additionally, a special keyword
forever can be specified as
expiration-time, which means the key has an
infinite lifetime and never expires. This substatement can be omitted,
in which case forever will be used by default.
Examples¶
The followings are a sample configuration to be delegated an IPv6 prefix from an
upstream service provider. With this configuration
dhcp6c
will send solicit messages containing an IA_PD option, with an IAID 0, on to
an upstream PPP link,
ppp0. After receiving some
prefixes from a server,
dhcp6c will then configure derived
IPv6 prefixes with the SLA ID 1 on a local ethernet interface,
ne0. Note that the IAID for the
id-assoc statement is 0 according to the default.
interface ppp0 {
send ia-pd 0;
};
id-assoc pd {
prefix-interface ne0 {
sla-id 1;
};
};
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:
keyinfo kame-key {
realm "kame.net";
keyid 1;
secret "5pvW2g48OHPvkYMJSw0vZA==";
};
One easy way of generating a new secret in the base64 format is to execute the
openssl(1) command (when available) as follows,
% openssl rand -base64 16
and copy the output to the
dhcp6c.conf file.
To include an authentication option for DHCPv6 authentication, the
interface statement should be modified and an
authentication statement should be added as follows:
interface ppp0 {
send ia-pd 0;
send authentication kame;
};
authentication kame {
protocol delayed;
};
interface fxp0 {
send ia-na 0;
};
SEE ALSO¶
dhcp6s.conf(5) dhcp6c(8)
HISTORY¶
The
dhcp6c.conf configuration file first appeared in the
WIDE/KAME IPv6 protocol stack kit.