Date: Fri, 17 Aug 2001 13:04:51 -0700 From: "Crist J. Clark" <cristjc@earthlink.net> To: Gabriel Ambuehl <gabriel_ambuehl@buz.ch> Cc: Fernando Gleiser <fgleiser@cactus.fi.uba.ar>, questions@FreeBSD.ORG Subject: Re: Host unable to ping/access its own IPs Message-ID: <20010817130451.B306@blossom.cjclark.org> In-Reply-To: <89159908005.20010817192806@buz.ch>; from gabriel_ambuehl@buz.ch on Fri, Aug 17, 2001 at 07:28:06PM %2B0200 References: <20010817141401.C9633-100000@cactus.fi.uba.ar> <89159908005.20010817192806@buz.ch>
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On Fri, Aug 17, 2001 at 07:28:06PM +0200, Gabriel Ambuehl wrote: > -----BEGIN PGP SIGNED MESSAGE----- > > Hello Fernando, > > Friday, August 17, 2001, 7:18:08 PM, you wrote: > > > It is the documented behavior of IP aliases, from ifconfig(8): > > > alias Establish an additional network address for this > > interface. This > > is sometimes useful when changing network numbers, and > > one wishes > > to accept packets addressed to the old interface. If > > the address > > is on the same subnet as the first network address for > > this in- > > terface, a netmask of 0xffffffff has to be specified. > > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > There was a post some time ago explaining why. > > Any WTF did it work for me the last couple of months on another > machines with the proper netmask then? > > Remember: documenting a bug doesn't fix it (else MS soft would be > much more stable....) > > But the above isn't correct. It strikes me for any two IPs from the > same subnet, not only for such that are in the same subnet as the > first one. FreeBSD does not like the ambiguity. If you have a.b.c.10 and a.b.c.11 on a 0xffffff00 network, which one will be used as the source address when you try to connect to a.b.c.12? To eliminate the ambiguity, one address is the "primary" one with 0xffffff00 and the second (and any others) is an "alias" with the 0xffffffff mask. I am not aware of any reason this behavior could be considered a bug since I cannot think of any RFCs that require some other behavior (not that it is not possible I'm forgeting something). -- Crist J. Clark cjclark@alum.mit.edu To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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