Re: Help: iptables NAT broken with pppoe

[Jason Opperisano <opie@817west.com>]

On Mon, May 09, 2005 at 12:56:13AM -0500, Taylor, Grant wrote:
> Ok.  I've never heard or seen reference to /proc/sys/net/ipv4/ip_dynaddr 
> before and I'm not sure what its purpose is let alone that it is requried.  
> Does any one have any more information on what it is and what its purpose 
> is?

************************************************************************
$ cat /usr/src/linux-2.6.11/Documentation/networking/ip_dynaddr.txt 

  IP dynamic address hack-port v0.03
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  This stuff allows diald ONESHOT connections to get established
  by dynamically changing packet source address (and socket's if
  local procs).  It is implemented for TCP diald-box connections(1)
  and IP_MASQuerading(2).

  1)  Socket (and packet) source address is rewritten ON RETRANSMISSIONS
      while in SYN_SENT state (diald-box processes).
  2)  Out-bounded MASQueraded source address changes ON OUTPUT (when
      internal host does retransmission) until a packet from outside is
      received by the tunnel.

  This is specially helpful for auto dialup links (diald), where the
  ``actual'' outgoing address is unknown at the moment the link is going
  up. So, the *same* (local AND masqueraded) connections requests that
  bring the link up will be able to get established.

  [*] At boot, by default no address rewriting is attempted. 
  To enable:
     # echo 1 > /proc/sys/net/ipv4/ip_dynaddr
  To enable verbose mode:
     # echo 2 > /proc/sys/net/ipv4/ip_dynaddr
  To disable (default)
     # echo 0 > /proc/sys/net/ipv4/ip_dynaddr

  Enjoy!

  -- Juanjo  <jjciarla@raiz.uncu.edu.ar>
************************************************************************

-j

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