DHCP Options

Policy Filter

Code

Length

Variable. Minimum length is 8 octets for a single destination-and-mask pairing. Length increases in multiples of 8 octets for each additional pairing used.

Value

Two consecutive, unsigned 32-bit integers indicating a paired value, consisting of an IP address followed by a subnet mask.

Description

Specifies policy filters for nonlocal source routing on the client. The filters consist of a list of IP address and mask pairs specifying destination-and-mask pairs for which to filter source routes of any incoming datagrams. The client discards any source routed datagram with a next-hop address that does not match one of the filters. For further information about policy filtering as it applies to this option type, see RFC 1122, "Requirements for Internet Hosts—Communication Layers."

Structure

Code	Length	Address 1	Mask 1
21	n	a1, a2, a3, a4	m1, m2, m3, m4
		Address 2	Mask 2
		a1, a2, a3, a4	m1, m2, m3, m4, ...