Re: Can we kill net-tools, please?

[Russ Allbery <rra@debian.org>]

Bjørn Mork <bjorn@mork.no> writes:

> I believe that is a mis-interpretation of that RFC.  The examples are
> all network addresses, but I don't think there is anything there that
> restricts the CIDR notation only to that class of IPv4 addresses.

> FWIW, the notation is much older and has been used for IPv4 address +
> mask long before that RFC or the introduction of the "ip" tool.  I am
> unable to find the original first use, but here's at least one older
> reference (from 1998):
> https://tools.ietf.org/html/rfc2373#section-2.3

>   "The text representation of IPv6 address prefixes is similar to the
>    way IPv4 addresses prefixes are written in CIDR notation.  An IPv6
>    address prefix is represented by the notation:

>       ipv6-address/prefix-length
>   "

> The IPv4 CIDR notation was obviously already well enough known to be
> used to explain the new IPv6 notation. I believe the above paragraph
> would be very confusing, to the point of not making sense at all, if the
> IPv4 notation was known to be used only for network address +
> prefix-length.

Yeah, I'm clearly incorrect about this, and I apologize for the noise (and
appreciate all the good information).  I'm also now remembering, to my
embarassment, that I'd already ranted about and been corrected on this
before and then didn't retain that.  I suppose that shows how little I
deal with the ip tool.  (I probably should alias ifconfig to something
that reminds me to use ip to force myself to do the mental conversion.)

I apparently haven't gotten over my initial confusion when I ran into it
for the first time, but that isn't a good idea not to use the notation,
and I do see the merits.  Hopefully this time I'll remember and learn and
not forget the whole conversation again!

-- 
Russ Allbery (rra@debian.org)               <http://www.eyrie.org/~eagle/>