Re: [RFD] iptables: mangle table obsoletes filter table

From: Patrick McHardy
Date: Fri Oct 12 2007 - 08:32:26 EST


Al Boldi wrote:
>>>The problem is that people think they are safe with the filter table,
>>>when in fact they need the prerouting chain to seal things. Right now
>>>this is only possible in the mangle table.
>>
>>Why do they need PREROUTING?
>
>
> Well, for example to stop any transient packets being forwarded. You could
> probably hack around this using mark's, but you can't stop the implied route
> lookup, unless you stop it in prerouting.


This also works fine in FORWARD with a little extra overhead.
If you really have to save resources, you should use PREROUTING/raw
to also avoid the creation of a connection tracking entry.

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