From: Grant Taylor <gtaylor@riverviewtech.net>
To: lartc@vger.kernel.org
Subject: Re: [LARTC] Hardware Configuration Ideas
Date: Wed, 17 Aug 2005 06:12:45 +0000 [thread overview]
Message-ID: <4302D55D.8090008@riverviewtech.net> (raw)
In-Reply-To: <!~!UENERkVCMDkAAQACAAAAAAAAAAAAAAAAABgAAAAAAAAAENEVIhFsNkiQ6vTBNVSNQcKAAAAQAAAAJ07bVuJvEUWsDJDH0zUe+gEAAAAA@web-profile.net>
> Yes. In fact most cases of "advanced" firewalling only mean that you have a
> stupid fw-design, like hundreds/thousands of rules in one chain :-). Usually can
> be optimised by using sub-chains, ipset and/or ipt_ACCOUNT.
If someone has hundreds of rules in one chain (with out a _*VERY*_ good reason and even then) they need to be shot on the spot. For performance reasons such a chain should be broken out in to a tree of chains an subchains that are jumped to in an attempt to minimize the number of rules that have to be traversed to get a match on any given packet.
What I was referring to by advanced firewalling was such things as running things like "-p udp -s 0.0.0.0/32 -d 255.255.255.255/32 --sport 68 --dport 67 -m addrtype --src-type broadcast -m pkttype --pkt-type broadcast" for DHCP requests. or complex SSH Brute Force prevention chains / rules, or recent lists to control what types of traffic will be valid based on what you have sent or is not valid b/c you have not sent any thing, or should packets with the reset flag have the ack flat set or not, etc.
Grant. . . .
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next prev parent reply other threads:[~2005-08-17 6:12 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-08-15 20:53 [LARTC] Hardware Configuration Ideas Mihai Vlad
2005-08-16 13:34 ` Nickola Kolev
2005-08-16 16:38 ` Taylor, Grant
2005-08-16 17:17 ` Peter Surda
2005-08-16 17:21 ` Peter Surda
2005-08-17 6:12 ` Grant Taylor [this message]
2005-08-17 6:20 ` Grant Taylor
2005-08-17 15:46 ` Mihai Vlad
2005-08-17 17:33 ` Peter Surda
2005-08-17 19:18 ` Taylor, Grant
2005-08-17 20:36 ` Carl-Daniel Hailfinger
2005-08-17 21:06 ` Peter Surda
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