Date: Thu, 27 Sep 2001 21:00:18 -0500 (CDT) From: Joe Greco <jgreco@ns.sol.net> To: kutulu@kutulu.org, mupi@mknet.org, swear@blarg.net, oberman@es.net, freebsd-stable@FreeBSD.ORG Subject: Re: 127/8 continued Message-ID: <200109280200.VAA23645@aurora.sol.net>
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> This is a good explanation of the use of the first and last address of > any CIDR block, if you are trying to get maximum use from a small > space assignment (like a /29), there is really no reason to waste half > of a /30. Neither the broadcast nor the network address really serve a > useful purpose on /30. > > RFC 3021 describes a better way of addressing directly connected links > so half the space is not wasted. a /31 is used for each connection > allowing for 4 point to point connections from a /29. > > Whether FreeBSD routers can be configured to do this, I can't say, but > I suspect manual route commands would do the job. I know Juniper > routers support this capability. This is a bad explanation of the use of the first and last address of any CIDR block; it propagates the myth that a network and broadcast address is appropriate in all circumstances. It is true that a net and broadcast address are required by IP-on-Ethernet (and some similar multi-node networks). That is the only case where this is strictly true. The "current practice" described in RFC 3021 is anything but a current practice. Many people - including myself - have been using /31's for quite some time (read: since mid '90's) for point to point links. Most folks I know have already been pressed into using host addresses, /31's, or (in a few cases) ugly things like 192.168-net. FreeBSD does not appear to care on a point-to-point link, and hasn't for many years. Feel free to use it. -- Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net "We call it the 'one bite at the apple' rule. Give me one chance [and] then I won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN) With 24 million small businesses in the US alone, that's way too many apples. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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