Configuring DHCP

This section provides details for the configuration of DHCP on the S- K- and 7100-Series products.

Default DHCP Parameters lists DHCP parameters and their default values.

Default DHCP Parameters

Parameter	Description	Default Value
DHCP interface state	Specifies whether DHCP is enabled or disabled on a routing interface.	disabled
number of ping packets	Specifies the number of packets a DHCP server sends to an IP address before assigning the address to a requesting client.	2
ping timeout	Specifies the amount of time the DHCP server will wait for a ping reply from an IP address before timing out.	500 milliseconds
information refresh	Specifies the amount of time an DHCPv6 client will wait before requesting an option information refresh from the DHCPv6 server.	1 day

Enabling the DHCP Server and Configuring Automatic Address Assignment describes enabling the DHCP feature and client configuration.

Enabling the DHCP Server and Configuring Automatic Address Assignment

Step	Task	Command(s)
1	Enable DHCP on the routing interface in interface configuration command mode. DHCP is enabled by default.	ip dhcp server
2	Configure the local address pool to be used as a DHCP subnet for automatic IP address assignment.	ip local pool name subnet mask
3	Optionally, in local address pool configuration mode, exclude a range of IP addresses from the configured local pool subnet, specifying the beginning IP address and the number of additional addresses to exclude.	exclude ip-address number
4	Enter DHCP address pool configuration command mode for the specified pool.	ip dhcp pool name
5	Specify, in DHCP pool or client-class mode, the lease duration for an IP address dynamically assigned by a DHCP server to a client.	lease {days [hours] [minutes]}
6	In DHCP pool configuration mode, enable DHCP host configuration mode and optionally associate a client class with a DHCP client.	client-identifier unique-identifier [client-class name]
7	In DHCP pool configuration mode, specify parameters for a new DHCP client address.	hardware-address hardware-address [type]
8	Specify, in configuration command mode, the number of packets a DHCP Server sends to a pool address as part of a ping operation.	ip dhcp ping packets number
9	Specify, in configuration command mode, the number of milliseconds the DHCP server will wait for a ping reply from an IP address before timing out.	ip dhcp ping timeout milliseconds
10	In either configuration command mode or interface configuration mode, specify an always up source interface of IPv6 DHCP relay forwarded messages.	ipv6 dhcp relay source-interface interface
11	In interface command mode, configure the IPv6 DHCP relay agent to forward an IPv6 DHCP request from a client or other relay agent to the destination server or relay agent address.	ipv6 dhcp relay destination ipv6-address [destination-interface] [global] [vrf vrf]

Configuring Static IP Address Assignment describes how to configure the router.

Configuring Static IP Address Assignment

Task	Command(s)
Optionally, configure static IP address assignment in DHCP host configuration command mode by specifying an host IP address and network mask for a static DHCP binding. Use either the hardware-address or client-identifier command in DHCP pool configuration command mode to enter host configuration command mode.	host address [mask | prefix-length]

DHCP Client Configuration describes DHCP client configuration.

DHCP Client Configuration

Step	Task	Command(s)
1	Optionally, in DHCP host or pool configuration command mode, specify a domain name for the DHCP client.	domain-name name
2	Specify, in DHCP host or pool configuration command mode, one or more DNS server IP addresses to the DHCP clients.	dns-server address [address2...address8]
3	Specify, in DHCP host or pool configuration command mode, one or more NetBIOS WINS servers to the DHCP clients.	netbios-name-server address [address2...address8]
4	Specify, in DHCP host or pool configuration command mode, one or more node types to the DHCP clients. h-node — hybrid (recommended) b-node — broadcast p-node — peer-to-peer m-mode — mixed	netbios-node-type type
5	Optionally, in DHCP host or pool configuration command mode, assign routers to a DHCP client‘s default router list.	default-router address [address2...address8]
6	Specify, in DHCP host or pool configuration command mode, the default boot image for the DHCP client.	bootfile filename
7	Optionally, in DHCP host or pool configuration command mode, specify the next server in the DHCP server boot process.	next-server ip-address
8	Optionally, in DHCP host or pool configuration command mode, configure DHCP options.	option code [instance number] {ascii string | hex string | ip address}
9	Optionally, in client configuration command mode, assign a name to a DHCP client. Optionally, assign the named client to a client class.	client-name name [client-class name]
10	Optionally, in DHCP host or pool configuration command mode, configure a client class.	client-class name

Configuring DHCPv6 Information Option Pools describes enabling the DHCP feature and client configuration.

Configuring DHCPv6 Information Option Pools

Step	Task	Command(s)
1	In global configuration mode, create a DHCPv6 option pool and enter DHCPv6 pool configuration mode.	ipv6 dhcp pool poolname
2	In interface configuration mode, assign a DHCPv6 information option pool to a DHCPv6 server.	ipv6 dhcp server poolname

DHCPv6 Client Configuration describes DHCPv6 client configuration. All commands are configured in DHCPv6 pool configuration command mode.

DHCPv6 Client Configuration

Step	Task	Command(s)
1	Specify a domain name for the DHCPv6 client.	domain-name name
2	Specify one or more DNS server IP addresses to the DHCP clients.	dns-server address [address2...address8]
3	Specify one or more Network Information Services (NIS) domain names to return when responding to a DHCPv6 client request.	nis-domain-name domain [domain2...domain8]
4	Specify one or more Network Information Services (NIS) servers to assign to DHCPv6 clients.	nis-server address [address2...address8]
5	Specify one or more Network Information Services (NIS) version 2 domain names to return when responding to a DHCPv6 client request.	nisp-domain-name domain [domain2...domain8]
6	Specify one or more Network Information Services (NIS) version 2 servers to assign to DHCPv6 clients.	nis-server address [address2...address8]
7	Specify one or more Session Initiation Protocol (SIP) domain names to return when responding to a DHCPv6 client request.	sip-domain-name domain [domain2...domain8]
8	Specify one or more Session Initiation Protocol (SIP) servers to assign to DHCPv6 clients.	sip-server address [address2...address8]
9	Specify a Simple Network Time Protocol (SNTP) server to assign to DHCPv6 clients.	sntp-server address
10	Specify a unicast server to assign to DHCPv6 clients.	unicast-server address
11	Specify the amount of time a client should wait before refreshing information from the DHCPv6 server.	information-refresh {infinite | days [[hours] [minutes]}

Managing and Displaying DHCP describes how to manage and display DHCP.

Managing and Displaying DHCP

Task	Command(s)
To display IP DHCP bindings, in any command mode enter:	show ip dhcp binding [ip-address]
To display DHCP server statistics, in any command mode enter:	show ip dhcp server statistics
To delete one or all automatic DHCP address bindings, in configuration command mode enter:	clear ip dhcp binding {address | *}
To clear ip dhcp server statistics, in configuration command mode enter:	clear ip dhcp server statistics