[TUHS] conventions around zero padding in ip4

[Noel Chiappa]

    > From: Ron Minnich

    > I first learned in the 80s that 127.1 meant 127.0.0.1. I always assumed
    > zero padding was defined in a standard *somewhere*, but am finding out
    > maybe not. I talked to the IP OG, and he tells me that padding was not
    > in any standard.

I don't think it was very standardized; I've been working on the Internet
since 1977, and this is the very first I ever recall hearing of it! :-)


    > From: Bakul Shah 

    > The converse question is who came up with the a.b.c.d format where each
    > of a,b,c,d is in 0..255?

Again, that was not standardized at an early stage, but was, as best I can now
recall, just adopted by general usage (i.e. without any formal discussion).

There were other ways of specifying a IP address numerically, initially;
e.g. for a while at MIT we were using w,x,y,z (with w-z in octal - note the
','s, which were a syntatic tag for the octal form), which was easier to
interpret when looking at a packet dump on a PDP-11. Here:

  http://ana-3.lcs.mit.edu/~jnc/tech/unix/arc/tftp.c.1

is the source for a user command (from July, 1979) which allowed host
addresses to be given in that form.

I'm not sure who came up with the dotted decimal form; I suspect you'd need to
find some really old email archives, and look in that. There was, early on, a
list called "tcp-ip", used by people who were getting their machines ready for
the NCP->TCP/IP conversion. However, I suspect the 'dotted quad' predates
that; there was an even earlier mailing list, used in early experimental work,
by the group working on internet technology, whose name escapes me (it was
something like "internet working group").

It's possible that an IEN:

  https://www.rfc-editor.org/ien/ien-index.html

might mention the 'dotted quad' syntax; TCP and IP meeting minutes
would be a good place to start.

	Noel

PS: The A/B/C addresses are actually a moderately late stage of IP
addresses. At the very start, they were all '8 bits network numbers, and 24
bits of 'rest''.