nanog mailing list archives
Re: [nsp] known networks for broadcast ping attacks
From: "Jeffrey S. Curtis" <curtis () anl gov>
Date: Wed, 30 Jul 1997 16:06:02 -0500
Jay R. Ashworth writes: }Ought IP stack implementations not to refuse to reply to ECHO_REQUEST }packets with destination address which are broadcast addresses? Why? It's a useful tool. }Ok, yes, I know that CIDR makes this harder, but knowing which nets }fall on non-octet boundaries is non-obvious, too, and this particular }attack wasn't trying... It's not hard - a host knows its own subnet mask and therefore can calculate its broadcast address trivially (my IP address logical-AND my subnet mask, plus all ones in the zero-portion of the mask). }.255 is _always_ a broadcast address, no? Wrong - consider what happens on nets whose subnet mask is less than 24 bits long (I have many such nets). 10.1.1.255 is a unicast host address if the mask is /23, or /22, or... Jeff -- Jeffrey S. Curtis | Internetwork Manager Argonne National Laboratory | Email: curtis () anl gov 9700 South Cass Avenue, ECT-221 | Voice: 630/252-1789 Argonne, IL 60439 | Fax: 630/252-9689
Current thread:
- Re: [nsp] known networks for broadcast ping attacks Jeffrey S. Curtis (Jul 30)
- Re: [nsp] known networks for broadcast ping attacks Craig A. Huegen (Jul 30)
- Re: [nsp] known networks for broadcast ping attacks Craig A. Huegen (Jul 30)
- Re: [nsp] known networks for broadcast ping attacks Edward Henigin (Jul 30)
- Re: [nsp] known networks for broadcast ping attacks Jeremy Porter (Jul 30)
- <Possible follow-ups>
- Re: [nsp] known networks for broadcast ping attacks Jeffrey S. Curtis (Jul 30)
- Message not available
- Re: [nsp] known networks for broadcast ping attacks Jay R. Ashworth (Jul 30)
- Message not available
- Re: [nsp] known networks for broadcast ping attacks Craig A. Huegen (Jul 30)
- Re: [nsp] known networks for broadcast ping attacks prue (Jul 30)
- Re: [nsp] known networks for broadcast ping attacks Alex.Bligh (Jul 31)
- Re: [nsp] known networks for broadcast ping attacks Sean Donelan (Jul 30)
- Re: [nsp] known networks for broadcast ping attacks Steve Nash (Jul 30)