ipid-debuggery (was Re: [e2e] ICMP & TCP segments with IP ID = 0?

[Francesco Potorti`]

   The interesting question is what status do such efforts have.  If they
   make use of a feature in the protocol that everyone is supposed to
   implement, and use that feature for a purpose beyond that which the
   protocol architects intended is that (a) wrong; (b) a second-class
   usage [e.g., they can't complain if people don't implement the feature]; or
   (c) a use of the protocol entitled to equal credence with work done before?

An IP ID of 0 is legal as any other value.

Incrementing IP  ID when DF is set  is not mandated by  any document, as
far as I know, and not even recommended.

If the architect of an IP layer can nonetheless increment it without too
much effort, that is a good think,  because it turns out to be useful in
debugging, tracing, measuring, experimenting.

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Francesco Potortì (researcher)         Voice: +39 050 315 3058 (op.2111)
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