Spoofed Packet Tracker (Was Re: SMURF amplifier block list)

Jared Mauch jared at puck.nether.net
Mon Apr 20 16:15:22 UTC 1998

	MCI has a tool to track spoofed packets, which is the orgin of
any DoS today.

	You can get it from ftp.mci.net:/pub/security/dostrack742812.tar

	That will trace it to the edge of your network, then you need to
work with the other providers to track it past that point.

	If it's within your network, you should filter it either by
using ip verify unicast reverse-path on the serial interfaces or
via acls.

	ip verify unicast reverse-path is a feature in the fib images
by cisco.  Most large nsp's run these images, and they're now mainline,
so fire up your cco accounts and grab them.

	It drops packets that don't have the same return path, which works
for most customers that are single homed.

	- Jared

On a dark and stormy night, jlixfeld at idirect.ca said:
> Cisco has a method of tracing SMuRF, do they not?  Anyone know how they do
> it?!  Is it some imbedded thing, or do they call the owners of each
> network and pray that they have Ciscos?

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