IPv6 Type 0 Routing Header issues

Rob Austein sra at isc.org
Wed Apr 25 16:13:36 CEST 2007

At Wed, 25 Apr 2007 09:41:09 +0200 (CEST), Mohacsi Janos wrote:
> The current patch provided by OpenBSD/FreeBSD makes *BSD IPv6
> implemenation non-conformant to standard.

Sometimes violating the standard is the only reasonable thing for an
implementor to do.  The (IPv4) stack I worked on back in the '90s
shipped with forwarding of directed broadcast disabled by default,
long before anybody had heard of a "smurf attack".  The stack had a
compile-time option to enable forwarding of directed broadcast; from
memory, the documentation for that option went something like this:

  "This option exists solely to allow this software to comply with RFC
  1812.  Directed broadcast is dangerous, no matter what RFC 1812
  says.  Never enable this option under any circumstances."

Eventually the IETF gathered the collective will to update the
standard, but as implementors we would have been derelict in our duty
to our customers had we waited for the IETF.

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