Re: auto ip configuration

[Unknown <netfilter-devel@demultiplexer.de>]

hello,

please could you developer have a look at the description below
and tell whethet there is the way to make it?

example scenario:

client host-------------------gateway--------------------internet
10.0.0.1-----------192.168.0.1_______213.39.239.123-------------->>>

It would be nice to have a iptables Target acting like SNAT/MASQUERADE
but in the PREROUTING table doing the inverse job.
The goal shoud be to translate not valid ip-addresses into valid local
address space, so user not being able to change their ip-setting could
surf the net.

I am not experienced in kernel hacking so i would preffer to donate for
your work if it is something no one would have but me.

thanks in advance
jaroslaw


> dear list,
> 
> you know about people, which have some static ip configuration on their
> notebooks. they would like to connect to a smart gateway
> without the need to change anything. 
> 
> I would ask you whether this is possible to implement such a gateway
> using netfilter.
> 
> I alredy build a working example with some tools and scripting
> but it isn't really performant and it have a lot of "design errors".
> Simple speaking it is a farpd running box, where all incoming requests
> are logged through the bridging code. The Syslog output is piped
> into a script and the requested ip is assigned to the lan interface.
> Evil thing ;-)
> 
> I would preffer something like inverse SNAT/MASQUERADE.
> The difference would be, that:
> 	it applys to PREROUTING
> 	it does mapping from a big subnet (maybe 0/0) to a singe address or a
> range of addresses.
> 
> The farpd would point all clients to the gateway.
> Having rp_filter disabled all misconfigured packets incoming on a lan
> interface would be translated into a valid ip address.
> Then the usual routing would take place.
> The response packets would be back-natted into the clients idea of the
> gateway address.
> 
> Would please someone give me a pointer.
> Am I completly wrong with this?
> 
> regards
> jaroslaw
>