Configuration parameters and options

DHCP provide a mechanism whereby the server can provide the client with information about how to configure its network interface (e.g., subnet mask), and also how the client can access various network services. It is achieved by options and parameters which are transmitted to the clients. Consider the most frequently used parameters:

range [dynamic-bootp] low-address [high-address];

Determines the range (upper and lower limits) IP-addresses available for dynamic using. Parameter range should be associated with the operator subnet.

hardware type address;

Determines client hardware address. Hardware option should be associated with an operator host.

fixed-address address[, address...];

Assigns to the host one or more fixed IP-address. This option is valid only in conjunction with the operator of host. If host has multiple addresses, client will get IP address that is valid for the network segment to which it is connected to. If such an address is not in the configuration, client does not get any parameters.

autoritative;

not autoritative;

Indicates the competent of the DHCP server. By default it is autoritative. not autoritative can be used if the the DHCP server is not use to assign addresses to clients. DHCP server can serve multiple networks, thus have the authority to assign addresses in some segments and not have in others.

allow keyword;

deny keyword;

Determines how server should need to respond to requests of different types. Keyword (keyword) specifies the type of permit (allow) or forbidden (deny) requests. There are next keywords:

- unknown-clients – determines the ability to assign dynamic addresses to unknown clients. By default, permit.

- bootp – determines the need to respond to BOOTP requests. By default, permit.

- booting – used within the declaration of host to indicate the need to respond to a particular client. By default, permit.

Operators dhcpd options define all the standard settings DHCP, described in the existing RFC. Consider the most useful of them.

option subnet-mask mask;

Specifies the subnet mask in decimal don notation. If the subnet-mask is not defined in the file dhcpd.conf, dhcpd uses a subnet mask defined in the operator subnet.

option routers address [, address...];

Specifies available routers in order of preference.

option domain-name-servers address [, address...];

Specifies available domain name servers in order of preference.

option lpr-servers address [, address...];

Specifies available to customers print servers LPR in order of preference.

option host-name host;

Specifies the client’s host name.

option domain-name domain;

Specifies domain name.

option broadcast-address address;

Specifies broadcast address for client’s subnet.

option static-routes destination gateway [, destination gateway...];

Specifies static route which available to the client. The default route cannot be specified in such a way.

option nis-domain string;

string that defines the name is NIS domain (Network Information Services).

option nis-servers address [, address...];

Specifies the IP-addresses of vailable NIS servers in order of preference.

Дата добавления: 2015-08-27