---
name: "dhcp6s.conf"
section: "5"
platform: "linux"
package: "wide-dhcpv6-server"
version: "20080615-24"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/dhcp6s.conf"
---

# dhcp6s.conf(5)

DHCPv6 server configuration file

## NAME

**dhcp6s.conf** – DHCPv6 server configuration file

## SYNOPSIS

*/etc/wide-dhcpv6/dhcp6s.conf*

## DESCRIPTION

The **dhcp6s.conf** file contains configuration information for KAME's DHCPv6 server, **dhcp6s**. 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.*

## Include statement

An include statement specifies another configuration file to be included. The format of an include statement is as follows:

-

  **include** *"filename"*; Where *"filename"* is the name (full path) of the file to be included.

## Option statement

An option statement specifies configuration parameters provided for every client. The format of the statement is as follows.

-

  **option** *option-name* \[*option-value*\] ; The following options can be specified in an option statement.

  -

    **domain-name-servers** *dns-address* \[*dns-addresses...*\]; provides DNS server address(es). Each *dns-address* must be a numeric IPv6 address. Multiple server addresses can also be specified by a sequence of these statements.

  -

    **domain-name** *"dns-name"*; provides a domain name of a DNS search path. Multiple names in the path can be specified by a sequence of these statements.

  -

    **ntp-servers** *ntp-address* \[*ntp-addresses...*\]; provides NTP server address(es). Each *ntp-address* must be a numeric IPv6 address. Multiple server addresses can also be specified by a sequence of these statements.

  -

    **sip-server-address** *sip-server-address* \[*sip-server-addresses...*\]; provides SIP server address(es). Each *sip-server-address* must be a numeric IPv6 address. Multiple server addresses can also be specified by a sequence of these statements.

  -

    **sip-server-domain-name** *"sip-server-domain-name"*; provides a domain name of a SIP server. Multiple names in the path can be specified by a sequence of these statements.

  -

    **nis-server-address** *nis-server-address* \[*nis-server-addresses...*\]; provides NIS server address(es). Each *nis-server-address* must be a numeric IPv6 address. Multiple server addresses can also be specified by a sequence of these statements.

  -

    **nis-domain-name** *"nis-domain-name"*; provides a NIS domain name. Multiple names in the path can be specified by a sequence of these statements.

  -

    **nisp-server-address** *nisp-server-address* \[*nisp-server-addresses...*\]; provides NIS+ server address(es). Each *nisp-server-address* must be a numeric IPv6 address. Multiple server addresses can also be specified by a sequence of these statements.

  -

    **nisp-domain-name** *"nisp-domain-name"*; provides a NIS+ domain name. Multiple names in the path can be specified by a sequence of these statements.

  -

    **bcmcs-server-address** *bcmcs-server-address* \[*bcmcs-server-addresses...*\]; provides BCMCS server address(es). Each *bcmcs-server-address* must be a numeric IPv6 address. Multiple server addresses can also be specified by a sequence of these statements.

  -

    **bcmcs-server-domain-name** *"bcmcs-server-domain-name"*; provides a domain name of a BCMCS server. Multiple names in the path can be specified by a sequence of these statements.

  -

    **refreshtime** *interval*; specifies the refresh time of stateless information that does not have particular lease duration in seconds. This option is only applicable to stateless configuration by information-request and reply exchanges.

## 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.

  -

    **allow** *allow-options* ; This statement specifies DHCPv6 options accepted by the server. Currently only *rapid-commit* can be specified in an **allow** statement, which specifies the server to accept a rapid-commit option in solicit messages.

  - **preference** *pref*;

    This statement sets the server's preference value on the interface to the value *pref*. The specified value will be contained in a preference option of advertise messages. The preference value must be a decimal integer and be between 0 and 255 (inclusive.)

  - **address-pool** *pool* *pltime* \[*vltime*\];

    This statement assigns an address pool *pool* to the interface. When **dhcp6s.conf** receives a allocation request for an IA-NA, it assigns one IPv6 address from this pool. The specified pool name will be defined in a pool statement. Regarding the *pltime* and *vltime* , please see the explanation in the *prefix* substatement in host statement section.

## Host statement

A host statement specifies configuration parameters for a particular client. The generic format of a host statement is as follows:

-

  **host** *name* { *substatements* }; *name* is an arbitrary string. It does not affect server's behavior but is provided for readability of log messages. Possible substatements are as follows.

  - **duid** *ID*;

    This statement defines the client's DHCP unique identifier (DUID). *ID* is a colon-separated hexadecimal sequence where each separated part must be composed of two hexadecimal values. This statement is used to identify a particular host by the server and must be included in a host statement.

  - **prefix** *ipv6-prefix* *pltime* \[*vltime*\];

    This statement specifies an IPv6 prefix to be delegated to the client. *ipv6-prefix* is a string representing a valid IPv6 prefix (see the example below). *pltime* and *vltime* are preferred and valid lifetimes of the prefix, respectively. When the latter is omitted, it will be set to the same value of *pltime.* A positive decimal number or a special string **infinity** can be specified as a lifetime. A decimal number provides the lifetime in seconds, while **infinity** means the corresponding lifetime never expires. When both lifetimes are specified, *pltime* must not be larger than *vltime*. Multiple prefixes can be specified, each of which is given by a single **prefix** statement. In that case, all or some of the specified prefixes will be delegated to the client, based on required parameters by the client.

  - **address** *ipv6-address* *pltime* \[*vltime*\];

    This statement specifies an IPv6 address to be assigned to the client. Everything is same as  *prefix* option, except that you do not need specify prefix length.

  - **delayedkey** *keyname*;

    This statement specifies a secret key shared with the client for the DHCPv6 delayed authentication protocol. *keyname* is a string that identifies a particular set of key parameters. A separate **keyinfo** statement for *keyname* must be provided in the configuration file. When this statement is specified and the client includes an authentication option for the delayed authentication protocol in a Solicit message, **dhcp6s** will perform the authentication protocol for succeeding message exchanges.

## Pool statement

A pool statement specifies an address pool for a particular interface. The generic format of a pool statement is as follows:

-

  **pool** *name* { *substatements*; }; *name* is an arbitrary string. It does not affect server's behavior but is provided for readability of log messages. Possible substatements are as follows.

  - **range** *min-addr* **to** *max-addr*

    This substatement defines the range of addresses allocated for the pool, i.e. from  *min-addr* to *max-addr.*

## Keyinfo statement

This statement defines a secret key shared with a client to authenticate DHCPv6 messages. The format and the description of this statement is provided in [dhcp6c.conf(5)](/dhcp6c.conf/5.md). One important difference in the server configuration is, however, the *keyname* is referred from a **host** statement as described above.

## Examples

The followings are a sample configuration to provide a DNS server address for every client as well as to delegate a permanent IPv6 prefix 2001:db8:1111::/48 to a client whose DUID is 00:01:00:01:aa:bb.

```
option domain-name-servers 2001:db8::35;
host kame {
	duid 00:01:00:01:aa:bb;
	prefix 2001:db8:1111::/48 infinity;
};
```

If a shared secret should be configured in both the server and the client for DHCPv6 authentication, it would be specified in the configuration file as follows:

```
keyinfo kame {
        realm "kame.net";
        keyid 1;
        secret "5pvW2g48OHPvkYMJSw0vZA==";
};
```

And the **host** statement would be modified as follows:

```
host kame {
	duid 00:01:00:01:aa:bb;
	prefix 2001:db8:1111::/48 infinity;
        delayedkey kame;
};
```

## SEE ALSO

[dhcp6c.conf(5)](/dhcp6c.conf/5.md) [dhcp6s(8)](/dhcp6s/8.md)

## HISTORY

The **dhcp6s.conf** configuration file first appeared in the WIDE/KAME IPv6 protocol stack kit.