Redploying most of 127/8 as unicast public

Mark Andrews marka at isc.org
Thu Nov 18 00:20:35 UTC 2021


It’s a denial of service attack on the IETF process to keep bringing up drafts like this that are never going to be approved.  127/8 is in use.  It isn’t free.

Lots of bad attempts to justify a bad idea.

"The IPv4 network 127/8 was first reserved by Jon Postel in 1981 [RFC0776]. Postel's policy was to reserve the first and last network of each class, and it does not appear that he had a specific plan for how to use 127/8.”

Having a space for permission-less innovation and testing is a good thing.  Jon understood that.

"By contrast, IPv6, despite its vastly larger pool of available address space, allocates only a single local loopback address (::1) [RFC4291]. This appears to be an architectural vote of confidence in the idea that Internet protocols ultimately do not require millions of distinct loopback addresses.”

This is an apples-to-oranges comparison.  IPv6 has both link and site local addresses and an architecture to deliver packets to specific instances of each.  This does not exist in the IPv4 world.

"In theory, having multiple local loopback addresses might be useful for increasing the number of distinct IPv4 sockets that can be used for inter-process communication within a host. The local loopback /16 network retained by this document will still permit billions of distinct concurrent loopback TCP connections within a single host, even if both the IP address and port number of one endpoint of each connection are fixed.”

But it doesn’t deliver millions of end points.  Sorry you simulation will not work because we don’t have more that 65000 end points anymore.  Sorry RFC 1918 addresses are not always suitable.

"Reserved for <use>" is not the same as “Reserved”.

Mark

> On 18 Nov 2021, at 10:45, scott <surfer at mauigateway.com> wrote:
> 
> 
> 
> On 11/17/2021 1:29 PM, Jay R. Ashworth wrote:
>> This seems like a really bad idea to me; am I really the only one who noticed?
>> 
>> 
>> https://www.ietf.org/id/draft-schoen-intarea-unicast-127-00.html
>> 
>> 
>> That's over a week old and I don't see 3000 comments on it, so maybe it's just
>> me.  So many things are just me.
>> 
>> [ Hat tip to Lauren Weinstein, whom I stole it from ]
>> 
> ------------------------------------------------------------------------------------------------- 
> 
> 
> 
> Everyone's just tired of rehashing this stuff... ;)  I looked up the "IPv4 Unicast Extensions Project" the authors (S.D. Schoen, J. Gilmore and D. Täht) are a part of.
> 
> 
> 
> https://github.com/schoen/unicast-extensions
> 
> ------------------
> 
> Fixing the odd nooks and crannies still mildly broken in IPv4, by:
> 
> 	• Making class-e (240/4), 0/8, 127/8, 224/4 more usable
> 	• Adding 419 million new IPs to the world
> 	• Fixing zeroth networking
> 	• Improving interoperability with multiple protocols and tunnelling technologies
> 	• Supplying tested patches and tools that address these problems
> ------------------
> 
> Some of these are hardcoded in ASICs, I believe.  Change that! ;)
> 
> scott
> 

-- 
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742              INTERNET: marka at isc.org



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