lkml.org 
[lkml]   [2007]   [Jun]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/2] xt_connlimit (kernel) - connection limiting

On Jun 3 2007 18:00, Andrew Beverley wrote:
>On Sun, 2007-06-03 at 13:12 +0200, Jan Engelhardt wrote:
>> Adds the connlimit match that has been in POM-NG for a long time.
>>
>> * works with 2.6.22, xtables'ified and all that
>>
>> * will request nf_conntrack_ipv4 upon load
>> (otherwise it hotdrops every packet - a glitch that goes back
>> to at least 2.6.20.2)
>
>Excellent! This has been at the back of my mind for a while.
>
>Is there any chance of getting UDP flows added as well as TCP
>connections?

I dare to say it's easy. The real problem is rather, that UDP is
connectionless, so for one, connlimit can, by definition of the word
'connectionless', not apply to UDP, though it is technically
possible. Second, because UDP "connections" "fly" (timeout after 30
seconds), just spewing one UDP packet out may kill another connection
(e.g. if you use connlimit in conjunction with DROP or REJECT).
What's more, UDP packets can be easily forged, much more than TCP, so
anyone on the same subtree (not subnet, because that's something
different) can send a bogus UDP packet and stop your connections from
working.
Let's see how to implement UDP counting...


Jan
--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-06-03 19:23    [W:0.036 / U:0.116 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site