1This is an experimental demonstration target which inverts the source 2and destination fields in the IP header and retransmits the packet. 3It is only valid in the 4.BR INPUT , 5.B FORWARD 6and 7.B PREROUTING 8chains, and user-defined chains which are only called from those 9chains. Note that the outgoing packets are 10.B NOT 11seen by any packet filtering chains, connection tracking or NAT, to 12avoid loops and other problems. 13