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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: [nsp] known networks for broadcast ping attacks
On Wed, 30 Jul 1997, Jay R. Ashworth wrote: > .255 is _always_ a broadcast address, no? What if you supernet multiple /24's into something larger (say a /21) for an obnoxiously large flat network. You'd have multiple hosts with x.y.z.255 addresses that were not broadcast addresses...no? It probably only makes sense to filter broadcast targeted traffic coming into your network, since you can only be sure what's a broadcast address within your own net. Somebody recently mentioned no ip directed-broadcast. That seems to stop incoming packets for your broadcast address...so someone then can't use your site as a ping amplifier to attack someone else by sending ping packets to your broadcast address claiming a source address of the intended victim. For similar reasons, I block udp chargen requests and replies at our GNV border router. ------------------------------------------------------------------ Jon Lewis <[email protected]> | Unsolicited commercial e-mail will Network Administrator | be proof-read for $199/message. Florida Digital Turnpike | ________Finger [email protected] for PGP public key_______
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