Date: Mon, 28 Aug 2000 18:41:22 -0500 From: Dave McKay <dave@mu.org> To: Dragos Ruiu <dr@kyx.net> Cc: Alfred Perlstein <bright@wintelcom.net>, "Col.Panic" <panic@satan.antix.org>, freebsd-security@FreeBSD.ORG Subject: Re: your mail (fwd) Message-ID: <20000828184122.A83217@elvis.mu.org> In-Reply-To: <0008281356040S.20616@smp.kyx.net>; from dr@kyx.net on Mon, Aug 28, 2000 at 01:54:41PM -0700 References: <Pine.BSF.4.21.0008281105250.60987-100000@satan.antix.org> <20000828111254.S1209@fw.wintelcom.net> <0008281356040S.20616@smp.kyx.net>
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An nmap scan doesn't generate 3500 icmp's per second, or 3500 of any packet per second. Dragos Ruiu (dr@kyx.net) wrote: > I get this message regularly whenever I use an application that generates > a lot of ICMP from a FreeBSD machine, like when I UDP nmap a FreeBSD > target for instance. --dr > > On Mon, 28 Aug 2000, Alfred Perlstein wrote: > > > > Sep 19 00:17:56 shell /kernel: icmp-response bandwidth limit 3505/200 pps > > > > Sep 19 00:17:57 shell /kernel: icmp-response bandwidth limit 3503/200 pps > > > > Sep 19 00:17:58 shell /kernel: icmp-response bandwidth limit 3505/200 pps > > > > Sep 19 00:17:59 shell /kernel: icmp-response bandwidth limit 3502/200 pps > > > > * Col.Panic <panic@satan.antix.org> [000828 11:09] wrote: > > > I have an interesting appendage to add to this answer. I have ICMP shut > > > down at the router, and I get the same messages from my new 4.1-STABLE > > > system. I can understand if somebody is spoofing ICMP packets, but if > > > they are, how are the replies getting to my machine? > > > > > > I've looked into it, and there isn't anybody logged into the machine for > > > when this occurs. I'm at a loss. > > > > It's an icmp _response_ limit, meaning it limits the amount of icmp > > error messages your machine will generate in repsonse to bogus > > connections or listen queue overflows. > > > > most likely an ACK/SYN attack of some sort or a server unable to > > handle its listen queue (incomiming connections) > > > > -Alfred > > > > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > > with "unsubscribe freebsd-security" in the body of the message > -- > dursec.com ltd. / kyx.net - we're from the future > pgp fingerprint: 18C7 E37C 2F94 E251 F18E B7DC 2B71 A73E D2E8 A56D > pgp key: http://www.dursec.com/drkey.asc > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-security" in the body of the message -- Dave McKay Network Engineer - Google Inc. dave@mu.org - dave@google.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
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