[dns-operations] TLD(s) for private use

James Stevens James.Stevens at jrcs.co.uk
Thu Sep 7 15:27:39 UTC 2017

On 07/09/17 15:51, Stephane Bortzmeyer wrote:
> On Thu, Sep 07, 2017 at 12:36:51PM +0100,
>   James Stevens <James.Stevens at jrcs.co.uk> wrote
>   a message of 39 lines which said:
>> People do, generally, use rfc1918 IP space instead of just picking
>> random numbers.
>> Imagine the chaos we would be having now, if each DSL router had a
>> different random subnet on it.
> I disagree, having random numbers is the right way (it prevents
> collisions). See RFC 4193.

Only viable if you have enough address space to work with in the first 
place AND still requires that the address blocks are picked from a 
subset of addresses specifically reserved for local use. It just 
describes a different mechanism for picking, other than human "ingenuity".

My original context was rfc1918, and rfc1918 is v4 only. The entire v4 
address space just isn't big enough to provide globally unique random 
blocks, even if the future had been known at the time the blocks started 
to be allocated.

May be more routers should pick a random fake TLD, instead (like mine) 
of having "lan" hard coded?

The point I was making was that if, in a world where rfc1918 didn't 
exist (which I'm analogising is the state we're in with DNS) and the 
result was that router / manufacturers / individuals simply picked any 
old v4 subnet of their choice, the result would be random parts of the 
internet unreachable from random locations - which I shortened to the 
word "chaos" as this is close to the effect it would have on ISP tech 

I seem to remember a story or two many years ago when Cisco(?) put one 
(or more) of its allocated, & actively used, address blocks as an 
example in a manual and people just copied it.


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