[e2e] ICMP & TCP segments with IP ID = 0?

[Bob Braden]

  *> 
  *> i think this is one of those "be conservative in what you send" things.  the 
  *> conservative thing to do, i would argue, is to obey the principle of least 
  *> surprise and send unique IDs; this is what systems expect, orthogonal from DF 
  *> or not DF.  (of course, the rest of the world should obey the second half: "be 
  *> liberal in what you accept", and so deal with ID == 0.)
  *> 
  *> not everything is (or can be) written down.  but, as i found out to my 
  *> incredible embarrassment with the telnet client in 4.3BSD [it *still* turns my 
  *> face red when i think of it!], if you find yourself going out of your way to 
  *> do something "out the ordinary" (out of the expected), it may well be the 
  *> "wrong" thing to do.
  *> 

Yes, exactly.

Bob Braden