SMURF amplifier block list

Tue Apr 14 09:39:10 UTC 1998

On Tue, 14 Apr 1998, Alex P. Rudnev wrote:

> The whole idea was to block attempts to make SMURF atatck originated from 
> your network, and this case the black list of addresses to be blocked 
> (it's the list of broadcast addresses used to amplify ICMP) joined with 
> the logging such attempts is quite usefull.

Ok, this I may agree with.  However, I contend that with appropriately
configured filters along your customer borders, that an attack wouldn't be
possible by a customer except to attack himself or another address which
matches the hole in the source address filter for the customer -> net
direction. 

Hopefully those holes are as small as possible.

On another note, could someone please mention again which IOS has the cool
"drop all packets from an interface which we don't have a matching route
pointing the other direction" feature?

- Forrest W. Christian (forrestc at imach.com) 
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