Date: Wed, 21 Apr 2004 15:44:45 -0600 From: Tillman Hodgson <tillman@seekingfire.com> To: freebsd-security@freebsd.org Subject: Re: Other possible protection against RST/SYN attacks (was Re: TCP RST attack Message-ID: <20040421214445.GX476@seekingfire.com> In-Reply-To: <4086E522.7090303@comcast.net> References: <6.0.3.0.0.20040420144001.0723ab80@209.112.4.2> <200404201332.40827.dr@kyx.net> <20040421111003.GB19640@lum.celabo.org> <6.0.3.0.0.20040421121715.04547510@209.112.4.2> <20040421165454.GB20049@lum.celabo.org> <6.0.3.0.0.20040421132605.0901bb40@209.112.4.2> <48FCF8AA-93CF-11D8-9C50-000393C94468@sarenet.es> <6.0.3.0.0.20040421161217.05453308@209.112.4.2> <75226E9B-93D3-11D8-90F9-003065ABFD92@mac.com> <4086E522.7090303@comcast.net>
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--Wb5NtZlyOqqy58h0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Apr 21, 2004 at 05:18:26PM -0400, Gary Corcoran wrote: > Charles Swiger wrote: > >The default TTL gets decremented with every hop, which means that a=20 > >packet coming in with a TTL of 255 had to be sent by a directly=20 > >connected system. [ip_ttl is an octet, so it can't hold a larger TTL=20 > >value.] >=20 > Huh? 255-- =3D=3D 254, not 0. A TTL of 255 just allows the maximum poss= ible > number of hops, before being declared hopelessly lost. Exactly -- if you see an incoming packet with a TTL of 255, it must've originated on a directly connected system /or it would've already been decremented to 254 or lower/. -T --=20 "Beware of he who would deny you information, for in his heart he dreams himself your master." --Wb5NtZlyOqqy58h0 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFAhutNDwp/vIKK/HsRAoN3AJ0aKDv4X5/wMIdY77mS8vzUnpKD8wCdHc7c ulf/IN+izwlMLk5BxDiDw40= =qlpc -----END PGP SIGNATURE----- --Wb5NtZlyOqqy58h0--
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