Date: Mon, 18 Jan 1999 08:54:45 +1100 (EST) From: "Daniel O'Callaghan" <danny@hilink.com.au> To: Justin Wolf <jjwolf@bleeding.com> Cc: ben@rosengart.com, "N. N.M" <madrapour@hotmail.com>, freebsd-security@FreeBSD.ORG Subject: Re: Small Servers - ICMP Redirect Message-ID: <Pine.BSF.3.96.990118085344.15297A-100000@enya.clari.net.au> In-Reply-To: <007701be4256$f01ff740$02c3fe90@cisco.com>
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On Sun, 17 Jan 1999, Justin Wolf wrote: > >> 2) About ICMP redirect messages, as I learned they could be used to make > >> our network disconnected and somthing. What's the way to prevent this > >> kind of attack? Does blocking this kind of ICMP on firewall and routers > >> cause any problem in connectivity and system behavior? > > > >I would block these messages from entering my network, absolutely. > > Keep in mind that flatly blocking all ICMP messages will prevent traces and > pings both in and out of your network. It will also effect certain > services... The best way to tailor this is to block everything and loosen > it up as necessary to keep things from breaking. It will also block useful things like source-quench. ICMP exists for a reason. Danny To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
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