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Mauro Carvalho Chehab9de1fcd2020-04-28 00:01:46 +02001.. SPDX-License-Identifier: GPL-2.0
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3==================================
Linus Torvalds1da177e2005-04-16 15:20:36 -07004IP dynamic address hack-port v0.03
Mauro Carvalho Chehab9de1fcd2020-04-28 00:01:46 +02005==================================
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Linus Torvalds1da177e2005-04-16 15:20:36 -07007This stuff allows diald ONESHOT connections to get established by
8dynamically changing packet source address (and socket's if local procs).
9It is implemented for TCP diald-box connections(1) and IP_MASQuerading(2).
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Mauro Carvalho Chehab9de1fcd2020-04-28 00:01:46 +020011If enabled\ [#]_ and forwarding interface has changed:
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Linus Torvalds1da177e2005-04-16 15:20:36 -070013 1) Socket (and packet) source address is rewritten ON RETRANSMISSIONS
14 while in SYN_SENT state (diald-box processes).
15 2) Out-bounded MASQueraded source address changes ON OUTPUT (when
16 internal host does retransmission) until a packet from outside is
17 received by the tunnel.
18
19This is specially helpful for auto dialup links (diald), where the
Mauro Carvalho Chehab9de1fcd2020-04-28 00:01:46 +020020``actual`` outgoing address is unknown at the moment the link is
Linus Torvalds1da177e2005-04-16 15:20:36 -070021going up. So, the *same* (local AND masqueraded) connections requests that
22bring the link up will be able to get established.
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Mauro Carvalho Chehab9de1fcd2020-04-28 00:01:46 +020024.. [#] At boot, by default no address rewriting is attempted.
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26 To enable::
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Linus Torvalds1da177e2005-04-16 15:20:36 -070028 # echo 1 > /proc/sys/net/ipv4/ip_dynaddr
Mauro Carvalho Chehab9de1fcd2020-04-28 00:01:46 +020029
30 To enable verbose mode::
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32 # echo 2 > /proc/sys/net/ipv4/ip_dynaddr
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34 To disable (default)::
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Linus Torvalds1da177e2005-04-16 15:20:36 -070036 # echo 0 > /proc/sys/net/ipv4/ip_dynaddr
37
38Enjoy!
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Mauro Carvalho Chehab9de1fcd2020-04-28 00:01:46 +020040Juanjo <jjciarla@raiz.uncu.edu.ar>