Date: Sat, 1 Apr 2000 15:47:24 -0800 From: Ulf Zimmermann <ulf@Alameda.net> To: "Aleksandr A.Babaylov" <babolo@links.ru> Cc: Eric Peterson <ericp@troikanetworks.com>, dot@dotat.at, nik@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: No route for 127/8 to lo0 (?) - another use for loopback subn et? Message-ID: <20000401154724.P95709@PacHell.TelcoSucks.org> In-Reply-To: <200004012349.DAA07016@aaz.links.ru>; from babolo@links.ru on Sun, Apr 02, 2000 at 03:49:53AM %2B0400 References: <C7CA595F9B9FD311A40D009027DC4A856E7E47@host03.troikanetworks.com> <200004012349.DAA07016@aaz.links.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sun, Apr 02, 2000 at 03:49:53AM +0400, Aleksandr A.Babaylov wrote: > Eric Peterson writes: > [Charset iso-8859-1 unsupported, filtering to ASCII...] > > Tony Finch [mailto:dot@dotat.at] wrote: > > > Nik Clayton <nik@freebsd.org> wrote: > > >> > > >> I thought that 127/8 was the "local net", and that > > >> packets sent to any of those addresses would go via > > >> the loopback interface. That seems to be how Linux > > >> and Windows 98 do things (the only systems I can > > >> check this on at the moment). Assuming that's the > > >> case, why does FreeBSD only add a a host route to > > >> 127.0.0.1, and not a network route for 127/8? > > > > > > I did some further investigation to see how old this > > > oddity is and it seems to be the way BSD has always > > > handled the loopback interface. There's an explicit > > > exclusion in the interface initialization code in in.c > > > that gives loopback interfaces a host route instead of > > > the network route that a normal interface gets and it's > > > been that way for 15 years. > > > > I always thought it was a great waste of network address > > space to devote an entire class A network to a single > > loopback address. An idea I got from a co-worker a while > > ago was to allow the 127.* (or some smaller subnet of 127) > > to be devoted to "intra-box addresses", for example: > > > > 1. A cluster of devices/slots within a chassis > > 2. A parallel processing machine > > 3. A multi-processor computer/device This is how Cisco is using it on their Catalyst switches for example. > > > > All of the above may have inter-processor communications > > that do not need to leave the chassis. Analogous to how > > the 192.168.* (RFC1918) addresses are used for intranets, > > these addresses wouldn't be allowed to be seen by the outside > > world (i.e. outside the "chassis"), but would permit internal > > IP communication without having to waste (and configure) a > > "real" IP net number. If these devices needed to get to the > > outside world, they could use NAT (again, analogously to the > > RFC1918 case). > I use addresses from 127/8 net for p2p connections > when security is useful. > TCP/IP pakets with 127.X.X.X has only one hop to live > and never be routed by BSD kernel. > may be 0/8 net is similar - I don't remember. > > -- > @BABOLO http://links.ru/ > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message -- Regards, Ulf. --------------------------------------------------------------------- Ulf Zimmermann, 1525 Pacific Ave., Alameda, CA-94501, #: 510-769-2936 Alameda Networks, Inc. | http://www.Alameda.net | Fax#: 510-521-5073 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20000401154724.P95709>