Re: [PATCH] fix small DoS on connect() (was Re: BUG: Unusual TCP Connect() results.)

From: Herbert Xu
Date: Sun Jun 12 2005 - 03:16:52 EST


On Sat, Jun 11, 2005 at 09:51:44PM +0200, Willy Tarreau wrote:
>
> Please note that if I only called it "small DoS", it's clearly because
> I don't consider this critical, but I think that most people involved
> in security will find that DoSes based on port guessing should be
> addressed when possible.

Sorry but this patch is pointless. If I wanted to prevent you from
connecting to www.kernel.org 80 and I knew your source port number
I'd be directly sending you fake SYN-ACK packets which will kill
your connection immediately.

If you want reliability and security you really should be using IPsec.
There is no other way.

Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
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