Redploying most of 127/8 as unicast public

Thu Nov 18 01:02:31 UTC 2021

Mark Andrews wrote:
> 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.

There are so many things wrong with this statement that I am not even 
going to try to enumerate them.

However suffice it to say that drafts like these are concrete 
documentation of non-groupthink and essentially you are advocating for 
self-censorship and loss of historical perspective.

Which given the state of IPv6 transition, perhaps more of that in the 
past would have been nice.

For example 
https://datatracker.ietf.org/doc/html/draft-fuller-240space-02 from 2008 
which fell prey to the "by the time this is usable IPv6 will have taken 
over" groupthink.

Objectively wrong.

Predictive self-fulfilling circular arguments of this sort should no 
longer be given any weight, and along your lines, should never even be 
brought up.

>
> 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.

Yes its a good idea to have space that is guaranteed to be available to 
every system regardless of its networking condition and that the host 
has deterministic control over the addressing used in that space.

However, it turns out that /8 was much too large. The extreme few 
instances of its usefulness at that size pale in comparison with even 
the possibility of its usefulness to the public.

So any attempt to adjust that should be given proper attention and 
serious thought.

>
> "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.

SO an IPv6 only system without any network interfaces can run multiple 
discrete instances of the same daemon accepting connections on the same 
TCP port? Can I script that, can I template that with hardcoded 
addresses, same as I can now for 127/8?

Good thing I can just use ::FFFF:127.0.0.1/104

>
> "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

Let them use IPv6 link local for their simulations.

>
>> 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?
>>>
>>>

Its only a relevant idea if you still care about IPv4. In which case, it 
might be a good idea.

Joe