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Re: Router modifications to deal with smurf

  • From: Craig A. Huegen
  • Date: Sun Apr 26 18:46:34 1998

On Sat, 25 Apr 1998, Rusty Zickefoose wrote:

==>        So, if someone, or possibly a group of someones, were to make the
==>following request to the various router vendors, would they be met with
==>approval by most of the readers? 
==>
==>        We requests that your routers be configurable, at the interface
==>level, to prevent the forwarding of an ICMP echo-request packet through an
==>interface that has a broadcast or wire address that matches the
==>destination address of that packet.  We also request that the default
==>configurations of your routers be modified to prevent said forwarding.

This is against RFC 1812.

RFC 1812, "Requirements for IP Version 4 Routers", Section 5.3.5,
specifies: 

---
   A router MAY have an option to disable receiving network-prefix-
   directed broadcasts on an interface and MUST have an option to
   disable forwarding network-prefix-directed broadcasts.  These options
   MUST default to permit receiving and forwarding network-prefix-
   directed broadcasts.
---

Someone has stated before that editor(s) of said RFC are aware of this and
have discussed the change in default.

Note that I'm not arguing that it *should* be the default, I'm just
arguing that vendors have implemented it this way because that's the way
they were told to in the RFC.  If after reading
http://www.quadrunner.com/~chuegen/smurf.txt, you think that I believe
directed-broadcasts should be on by default, go back and read agian. =)

Now, since this has been beaten past the jelly stage, can we please put
the topic to sleep?  Thank you. 

/cah






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