Date: Wed, 14 Nov 2012 08:05:10 +0000 From: Joe Holden <lists@rewt.org.uk> To: Sean Chittenden <sean@chittenden.org> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Re: 0.0.0.0/8 oddities... Message-ID: <50A350B6.7060600@rewt.org.uk> In-Reply-To: <C80C6D38-761B-469D-9650-9E54D5D870FE@chittenden.org> References: <DC8A0D79-8DF3-472F-9B1A-76BF8577A03C@chittenden.org> <50A20359.9080906@networx.ch> <7C614093-6408-49C6-8515-F6C09183453B@chittenden.org> <50A32FE7.2010206@rewt.org.uk> <7BE7E643-FB13-45DE-BA40-257B8ADFAA98@chittenden.org> <50A34675.2020709@rewt.org.uk> <082A52DA-3C04-46B7-A0C6-2F1CD814C01C@chittenden.org> <50A348F8.1050805@rewt.org.uk> <C80C6D38-761B-469D-9650-9E54D5D870FE@chittenden.org>
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On 14/11/2012 07:48, Sean Chittenden wrote: >>>> Regardless, why are you trying to do something that is unsupported by pretty much every vendor/operator/os? >>> >>> Status quo is fine and dandy if it's rational, backed up with a justification and can be understood, but I'm not seeing anything that suggests there's a good reason which indicates 0/8 shouldn't be used or supported. -sc >> >> It's official registration is for "self identification", "this" network doesn't mean the connected network. >> >> All in all, even allowing an address in 0/8 to be configured is a bug based on both a) the various RFCs and intended use and b) that's how everyone else accepts that it should work anyway, so RFC is irrelevant in that case. > > I think that's incorrect. 127/8 is used for hosts local to a physical server and 0/8 was intended for hosts "local to a network." In my definition, "this network" is data center-local, however there's nothing preventing that IP address range from being rack-local either, etc. 0.0.0.0/32 is a shortcut for saying "me on this network," which makes sense in the context of the wording in RFC 5735. Again, section 3 paragraph 1: > > 0.0.0.0/8 - Addresses in this block refer to source hosts on "this" > network. Address 0.0.0.0/32 may be used as a source address for this > host on this network; other addresses within 0.0.0.0/8 may be used to > refer to specified hosts on this network ([RFC1122], Section 3.2.1.3). > > In environments where DNS is an extra service that requires justification and would be an additional service that has to be secured, exclusive use of well known IP addresses is both convenient and useful, and the 0/8 network seems to have been defined for exactly this purpose. I admit the address range isn't in wide use atm, but I don't see a reason for it to not be. > > The fix Andre made appears to be correct, and IMO, should be merged in to -head and MFC'ed. > > http://www.secnetix.de/~olli/FreeBSD/svnews/index.py?r=242956 > > Cheers (& thank you Andre for making the commit). -sc > > -- > Sean Chittenden > sean@chittenden.org > It is quite clearly for self identification, major vendors and other reference OSes, eg Linux/Windows don't allow it, thus this is *wrong*. What we now have is a stack that's even more non-rfc/best practice compliant because *you* couldn't pick a sensible address like everyone else. There are 10 distinct ranges to choose from that whilst not being advisable, are not special cases and thus are valid. Andre, There are plenty of reserved ranges that *are* valid and *are* usable by other vendors/systems. Based on the rfc wording and vendor documents saying it should be a source address only and everyone else treating it as a special range (as it should be, like 224/4) and others such as link local, this should be reverted.
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