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+Performs a reverse path filter test on a packet.
+If a reply to the packet would be sent via the same interface
+that the packet arrived on, the packet will match.
+Note that, unlike the in-kernel rp_filter, packets protected
+by IPSec are not treated specially. Combine this match with
+the policy match if you want this.
+Also, packets arriving via the loopback interface are always permitted.
+This match can only be used in the PREROUTING chain of the raw or mangle table.
+Used to specifiy that the reverse path filter test should match
+even if the selected output device is not the expected one.
+Also use the packets' nfmark value when performing the reverse path route lookup.
+This will permit packets arriving from the network with a source address that is also
+assigned to the local machine.
+This will invert the sense of the match. Instead of matching packets that passed the
+reverse path filter test, match those that have failed it.
+Example to log and drop packets failing the reverse path filter test:
+iptables \-t raw \-N RPFILTER
+iptables \-t raw \-A RPFILTER \-m rpfilter \-j RETURN
+iptables \-t raw \-A RPFILTER \-m limit \-\-limit 10/minute \-j NFLOG \-\-nflog\-prefix "rpfilter drop"
+iptables \-t raw \-A RPFILTER \-j DROP
+iptables \-t raw \-A PREROUTING \-j RPFILTER
+Example to drop failed packets, without logging:
+iptables \-t raw \-A RPFILTER \-m rpfilter \-\-invert \-j DROP