Date: Wed, 24 Jan 2001 10:37:31 -0800 From: "Renaud Waldura" <renaud@waldura.com> To: "C. Stephen Gunn" <csg@waterspout.com> Cc: <freebsd-net@FreeBSD.ORG> Subject: Re: How to send arp request with no other traffic Message-ID: <000d01c08634$b6702c80$0402010a@biohz.net> References: <HJEEKLMFLKEOKHOKNPBMKEDBCJAA.patrick@netzuno.com> <006901c085ae$fae9bd80$0402010a@biohz.net> <20010124003305.B231@waterspout.com>
next in thread | previous in thread | raw e-mail | index | archive | help
> You can't really assume this will work. FreeBSD has a sysctl > to disable responses to broadcast/multicast ICMP-echo requests. You know what, I tried it with Windows machines, that do not reply to broadcast ping either, and it worked anyway. What gives? ----- Original Message ----- From: "C. Stephen Gunn" <csg@waterspout.com> To: "Renaud Waldura" <renaud@waldura.com> Cc: "Patrick Bihan-Faou" <patrick@netzuno.com>; <freebsd-net@FreeBSD.ORG> Sent: Tuesday, January 23, 2001 9:33 PM Subject: Re: How to send arp request with no other traffic > > On Tue, Jan 23, 2001 at 06:40:14PM -0800, Renaud Waldura wrote: > > > An amusing trick to populate the ARP table is to ping the broadcast address. > > Even if hosts do not reply to your ping packet (typically, Windows > > machines), they are entered in the ARP table. > > > > You still have to send a single packet, but it does all the work. > > You can't really assume this will work. FreeBSD has a sysctl > to disable responses to broadcast/multicast ICMP-echo requests. > > Exploitation of this "feature" is the basis for several denial > of service attacks. Spoof the origin address to an layer-3 > broadcast address and voila, amplified responses. :-( > > - Steve > > -- > C. Stephen Gunn <csg@waterspout.com> | Waterspout Communications, Inc. > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?000d01c08634$b6702c80$0402010a>