[e2e] ICMP & TCP segments with IP ID = 0?
minshall at redback.com
Wed May 16 10:20:44 PDT 2001
> Why are they evil? ipid is only useful for defragmentation, and perhaps
> to recover from bugs in IP checksum ...
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.
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