From nobody Thu Nov 04 06:05:13 2021 X-Original-To: freebsd-net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 54275182A831 for ; Thu, 4 Nov 2021 06:05:22 +0000 (UTC) (envelope-from shuriku@shurik.kiev.ua) Received: from mail.flex-it.com.ua (mail.flex-it.com.ua [193.239.74.7]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4HlCmK3Bdkz3PP1 for ; Thu, 4 Nov 2021 06:05:20 +0000 (UTC) (envelope-from shuriku@shurik.kiev.ua) Received: from [93.183.208.50] (helo=[192.168.200.124]) by mail.flex-it.com.ua with esmtpsa (TLS1.3) tls TLS_AES_128_GCM_SHA256 (Exim 4.94.2 (FreeBSD)) (envelope-from ) id 1miVs8-0004PL-6V for freebsd-net@freebsd.org; Thu, 04 Nov 2021 08:05:12 +0200 Message-ID: <3244c917-d08a-c72b-5b5a-f74233cf47f5@shurik.kiev.ua> Date: Thu, 4 Nov 2021 08:05:13 +0200 List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@freebsd.org MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: netmask for loopback interfaces Content-Language: ru To: freebsd-net@freebsd.org References: <202111032301.1A3N121R075694@mail.karels.net> From: Oleksandr Kryvulia In-Reply-To: <202111032301.1A3N121R075694@mail.karels.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 4HlCmK3Bdkz3PP1 X-Spamd-Bar: ++ Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of shuriku@shurik.kiev.ua designates 193.239.74.7 as permitted sender) smtp.mailfrom=shuriku@shurik.kiev.ua X-Spamd-Result: default: False [2.10 / 15.00]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; FROM_HAS_DN(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; R_SPF_ALLOW(-0.20)[+mx]; MIME_GOOD(-0.10)[text/plain]; TO_DN_NONE(0.00)[]; DMARC_NA(0.00)[shurik.kiev.ua]; NEURAL_SPAM_MEDIUM(1.00)[1.000]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_SPAM_SHORT(1.00)[1.000]; NEURAL_SPAM_LONG(0.40)[0.396]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:35297, ipnet:193.239.72.0/22, country:UA]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[] X-ThisMailContainsUnwantedMimeParts: N 04.11.21 01:01, Mike Karels пишет: > I have a pending change to stop using class A/B/C netmasks when setting > an interface address without an explicit mask, and instead to use a default > mask (24 bits). A question has arisen as to what the default mask should > be for loopback interfaces. The standard 127.0.0.1 is added with an 8 bit > mask currently, but additions without a mask would default to 24 bits. > There is no warning for missing masks for loopback in the current code. > I'm not convinced that the mask has any meaning here; only a host route > to the assigned address is created. Does anyone know of any meaning or > use of the mask on a loopback address? > > Thanks, > Mike > /8 mask on loopback prevetnts using of 127.x.x.x network anywhere outside of the localhost. This described in RFC 5735 [1] and 1122 [2] [1] https://datatracker.ietf.org/doc/html/rfc5735 [2] https://datatracker.ietf.org/doc/html/rfc1122