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DHCP Attributes for Address-Assignment Pools

Table 1 describes the DHCP client attributes that you can use with the dhcp-attributes statement when you configure address-assignment pools. Table 2 describes the DHCPv6 client attributes for configuring IPv6 address-assignment pools.

Table 1: DHCP Attributes

Attribute	Description	DHCP Option
boot-file	Boot filename advertised to the client, and used by the client to complete configuration.	67
boot-server	Boot server containing the boot file.	66
domain-name	Domain in which clients search for a DHCP server host.	15
grace-period	Grace period offered with the lease.	–
maximum-lease-time	Maximum lease time allowed by the DHCP server.	51
name-server	IP address of DNS server to which clients can send DNS queries.	6
netbios-node-type	NetBIOS node type.	46
option	User-defined options.	–
option-match	Option 82 value is mapped to named address range.	–
router	IP address for routers on the subnetwork.	3
server-identifier	IP address used as the DHCP source address	54
tftp-server	Trivial File Transfer Protocol (TFTP) server that the client uses to obtain the client configuration file.	150
wins-server	IP address of the Windows NetBIOS name server.	44

Table 2: DHCPv6 Attributes

Attribute	Description	DHCPv6 Option
dns-server	IPv6 address of DNS server to which clients can send DNS queries.	23
grace-period	Grace period offered with the lease.	–
maximum-lease-time	Maximum lease time allowed by the DHCP server.	–
option	User-defined options.	–
preferred-lifetime	Length of time, in seconds, that the DHCP server keeps the IPv6 prefix active. The DHCPv6 server sends this attribute to the client (router).	–
sip-server-address	IPv6 address of SIP outbound proxy server.	22
sip-server-domain-name	Domain name of the SIP outbound proxy server.	21
t1-percentage	Timer that, when it expires, the client (router) sends a request to the originating DHCP server requesting its lease (IP configuration) to be extended. If the lease period is limitless, the client's lease never expires and no request is required. However, because most leases are time-limited, the router monitors this timer and sends a request to the originating DHCP server to ensure that its lease is extended and normal operation continues. T1-percentage is specified as a percentage of the elapsed time for the preferred-lifetime value. This value is sent from the DHCP server to the router.	–
t2-percentage	Timer that, when it expires, the client (router) sends a request to any available DHCP server requesting its lease (IP configuration) to be extended. T2-percentage is sent from the DHCP server to the router. You specify t2-percentage as a percentage of the value of preferred-lifetime.	–
valid-lifetime	Length of time, in seconds, that the DHCP server keeps the IPv6 prefix valid.	–

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DHCP Attributes for Address-Assignment Pools

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Published: 2013-02-21