RE: adding rules - slow

["Покотиленко Костик" <casper@meteor.dp.ua>]

В Срд, 01/08/2007 в 09:24 +0200, Július Bemš пишет:
> Thank you very much ... good idea.
> But do you know why is iptables so slow? Because I think about writing my own utility for adding new rules.

date; I=0; while [ $I -lt 1000 ]; do I=`expr $I + 1`; iptables
>/dev/null 2>&1; done; date
Wed Aug  1 10:36:32 EEST 2007
Wed Aug  1 10:36:39 EEST 2007

As you can see just invoking iptables 1000 time from a shell takes 7
seconds on my machine. Shell is slow. Moreover when there are many rules
each iptables invocation does same checks that many times.
iptables-restore do much of the work once for all rules.

> -----Original Message-----
> From: netfilter-bounces@lists.netfilter.org [mailto:netfilter-bounces@lists.netfilter.org] On Behalf Of John A. Sullivan III
> Sent: Friday, July 27, 2007 11:38 PM
> To: Július Bemš
> Cc: netfilter@lists.netfilter.org
> Subject: Re: adding rules - slow
> 
> On Fri, 2007-07-27 at 23:30 +0200, Július Bemš wrote:
> > Hi,
> > 
> > When I need to add som rules (in my case 100) to some chain it takes various
> > time, depending on the number of existing rules in the chain. So when I add
> > 100 rules to empty chain, it takes 1.8sec. If tehere is 1000 rules int the
> > chain, it takes 4.5sec and if there is 10000 rules it takes 21sec. 
> > 
> > My problem is, that i need to add this rules to chain which contains 20000
> > rules in short time. I think, that the way of adding rules into chain is
> > very innefective. 
> > 
> > Could someone tell me how the adding works internally? What data structures
> > are used? Because I need solve this and find the way how to add new rules
> > quickly.
> > 
> > Thanks for replies
> > 
> > 
> We face the same problem on the ISCS project
> (http://iscs.sourceforge.net).  There, do to micro-perimeter network
> security, we frequently generate thousands or tens of thousands of rules
> with the click of a mouse.
> 
> We handle it by adding rules via iptables-restore rather than iptables.
> The load time difference is remarkable.  You write your rules into files
> with very similar syntax to iptables and then direct them into
> iptables-restore, e.g., 
> 
> iptables-restore < /etc/PEP/rules.txt
> 
> or, if you do not want to overwrite existing rules,
> 
> iptables-restore -n < /etc/PEP/runtimerules.txt
> 
> Hope this helps - John
-- 
Покотиленко Костик <casper@meteor.dp.ua>