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Re: 16 year old bug



On Dec 9, 11:48pm, der Mouse wrote:
}
} > That is, implementations are free to do whatever they like (these
} > days) if you use non-contig masks.
} 
} Sure; it's a quality-of-implementation issue, same as, say, accepting
} only (in today's terminology) mask widths that are multiples of 8 bits.

     In order to properly do CIDR you also need to do VLSM (Variable
Length Subnet Masking).  In the year 2010, any system that couldn't do
that would be considered so broken as to be essentially useless.  On
the other hand, in the year 2010, you can get away without
non-contiguous subnet masks 99.99% of the time.

} And yes, I ran into some such implementations back in the '80s; even
} then, we considered them annoyingly broken, much as I'd consider an
} implementation that misbehaved in the presence of noncontiguous masks.
} Or one that couldn't be configured to obey source routes.  Or any of
} endless other issues.
} 
} I recall talking with someone, once, who was involved in interop
} testing back in the '80s/'90s, before support for masks other than /8,
} /16, and /24 became "universal".  The tale as I remember it was that
} he'd tell vendors that "the mask on the show floor network is
} 255.255.252.0", with them looking worried; when feeling evil, he'd then

     This is a /22, not a big deal.

} tell them "and next year it'll be 255.255.250.0", followed by their

     This on the otherhand, I can't translate instantly, but I do know
that it is non-contiguous.

} (figuratively) running screaming, with a speed dependent on their
} ability to convert decimal to binary.  (I don't know how much truth
} there is in it; I suspect they never actually did that.  Pity.)
} 
}-- End of excerpt from der Mouse


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