Mauro Carvalho Chehab | 9de1fcd | 2020-04-28 00:01:46 +0200 | [diff] [blame] | 1 | .. SPDX-License-Identifier: GPL-2.0 |
| 2 | |
| 3 | ================================== |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4 | IP dynamic address hack-port v0.03 |
Mauro Carvalho Chehab | 9de1fcd | 2020-04-28 00:01:46 +0200 | [diff] [blame] | 5 | ================================== |
| 6 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | This stuff allows diald ONESHOT connections to get established by |
| 8 | dynamically changing packet source address (and socket's if local procs). |
| 9 | It is implemented for TCP diald-box connections(1) and IP_MASQuerading(2). |
| 10 | |
Mauro Carvalho Chehab | 9de1fcd | 2020-04-28 00:01:46 +0200 | [diff] [blame] | 11 | If enabled\ [#]_ and forwarding interface has changed: |
| 12 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 13 | 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 | |
| 19 | This is specially helpful for auto dialup links (diald), where the |
Mauro Carvalho Chehab | 9de1fcd | 2020-04-28 00:01:46 +0200 | [diff] [blame] | 20 | ``actual`` outgoing address is unknown at the moment the link is |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | going up. So, the *same* (local AND masqueraded) connections requests that |
| 22 | bring the link up will be able to get established. |
| 23 | |
Mauro Carvalho Chehab | 9de1fcd | 2020-04-28 00:01:46 +0200 | [diff] [blame] | 24 | .. [#] At boot, by default no address rewriting is attempted. |
| 25 | |
| 26 | To enable:: |
| 27 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | # echo 1 > /proc/sys/net/ipv4/ip_dynaddr |
Mauro Carvalho Chehab | 9de1fcd | 2020-04-28 00:01:46 +0200 | [diff] [blame] | 29 | |
| 30 | To enable verbose mode:: |
| 31 | |
| 32 | # echo 2 > /proc/sys/net/ipv4/ip_dynaddr |
| 33 | |
| 34 | To disable (default):: |
| 35 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 36 | # echo 0 > /proc/sys/net/ipv4/ip_dynaddr |
| 37 | |
| 38 | Enjoy! |
| 39 | |
Mauro Carvalho Chehab | 9de1fcd | 2020-04-28 00:01:46 +0200 | [diff] [blame] | 40 | Juanjo <jjciarla@raiz.uncu.edu.ar> |