From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=0.3 required=5.0 tests=MAILING_LIST_MULTI, RCVD_ILLEGAL_IP autolearn=no autolearn_force=no version=3.4.4 Received: (qmail 7620 invoked from network); 7 May 2022 18:51:43 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 7 May 2022 18:51:43 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 347889D439; Sun, 8 May 2022 04:51:40 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id A384D9CEEF; Sun, 8 May 2022 04:49:24 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id 0484C9CEEF; Sun, 8 May 2022 04:49:21 +1000 (AEST) Received: from sdaoden.eu (sdaoden.eu [217.144.132.164]) by minnie.tuhs.org (Postfix) with ESMTPS id DAB429CEEE for ; Sun, 8 May 2022 04:49:19 +1000 (AEST) Received: from kent.sdaoden.eu (kent.sdaoden.eu [192.0.2.2]) by sdaoden.eu (Postfix) with ESMTPS id B2ABF16059; Sat, 7 May 2022 20:49:17 +0200 (CEST) Received: by kent.sdaoden.eu (Postfix, from userid 1000) id 84C7782164; Sat, 7 May 2022 20:49:15 +0200 (CEST) Date: Sat, 07 May 2022 20:49:15 +0200 Author: Steffen Nurpmeso From: Steffen Nurpmeso To: ron minnich Message-ID: <20220507184915.nXfTT%steffen@sdaoden.eu> In-Reply-To: References: Mail-Followup-To: ron minnich , TUHS main list User-Agent: s-nail v14.9.24-235-gfda91a48ef OpenPGP: id=EE19E1C1F2F7054F8D3954D8308964B51883A0DD; url=https://ftp.sdaoden.eu/steffen.asc; preference=signencrypt BlahBlahBlah: Any stupid boy can crush a beetle. But all the professors in the world can make no bugs. Subject: Re: [TUHS] conventions around zero padding in ip4 X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: TUHS main list Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" ron minnich wrote in : |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. [side note: it's weird and wonderful |to still have so many people "present at the creation" of computing as |we know it still around, and to find they are so willing to answer |naive questions!] | |Padding is a standard in ip6, possibly because the addresses are so |long. :: is your friend. It was/is called compression there, and it was optional ("may") at first (in RFC 1884). RFC 1884 was an overall wonderful RFC, uppercase or lowercase are possible, leading zeros in a field were optional ("not necessary") etc. Unfortunately RFC 5952 loaded too much Sushi and Sake first, and turned this to a soldiers dream, "Leading zeros MUST be suppressed", "Shorten as Much as Possible", " "::" MUST NOT be used to shorten just one 16-bit 0 field", "longest run [.] MUST be shortened", "MUST [.] lowercase". Luckily SMTP seems to keep the elder |IP4 padding came up recently: the ip command interprets 10.2 as |10.2.0.0, whereas most things (golang libraries, ping, ...) interpret |it as 10.0.0.2. The latter interpretation accords with what I learned |40y ago. | |But, I find myself wondering: where was the first use of the IP4 zero |padding convention? I did not even know this is possible, but for special software like postfix SMTP etc., where it de-facto means "substring", so 10.2 is 10.2.0.0/16 (unless i am totally mistakent now). I could imagine that the introduction of CIDR notation as such (RFC 1519) played a role? I have had no idea of networks but modem beeps at all, coming from a staid pupils' desk with C64 -> DOS -> 4DOS / Windows 3.1 -> 4DOS / Windows95B (and then, and then!! It became real) , and there you had the GUI boxes which "zero padded" anything, unless i am mistaken. Btw ipcalc(1) (of RedHat aka https://gitlab.com/ipcalc) is incapable to deal with that abbreviation at all. So it maybe is a generation issue, like most other things. "'Hope i die before i get old". --steffen | |Der Kragenbaer, The moon bear, |der holt sich munter he cheerfully and one by one |einen nach dem anderen runter wa.ks himself off |(By Robert Gernhardt)