option policy-filter ip-address ip-address
                  [, ip-address ip-address...];

This option specifies policy filters for non-local source routing. The filters consist of a list of IP addresses and masks which specify destination/mask pairs with which to filter incoming source routes.

Any source routed datagram whose next-hop address does not match one of the filters should be discarded by the client.

See STD 3 (RFC1122) for further information.