DoD IP Space

Doug Barton dougb at
Wed Feb 10 17:50:56 UTC 2021

On 2/10/21 5:56 AM, Ca By wrote>
> The 3 cellular networks in the usa, 100m subs each, use ipv6 to uniquely 
> address customers. And in the case of ims (telephony on a celluar), it 
> is ipv6-only, afaik.

So that answers the question of how to scale networks past what can be 
done with 1918 space. Although why the phones would need to talk 
directly to each other, I can't imagine.

I also reject the premise that any org, no matter how large, needs to 
uniquely number every endpoint. When I was doing IPAM for a living, not 
allowing the workstations in Tucson to talk to the printers in Singapore 
was considered a feature. I even had one customer who wanted the 
printers to all have the same (1918) IP address in every office because 
they had a lot of sales people who traveled between offices who couldn't 
handle reconfiguring every time they visited a new location. I thought 
it was a little too precious personally, but the customer is always 
right.  :)

Sure, it's easier to give every endpoint a unique address, but it is not 
a requirement, and probably isn't even a good idea. Spend a little time 
designing your network so that the things that need to talk to each 
other can, and the things that don't have to, can't. I did a lot of 
large multinational corporations using this type of design and never 
even came close to exhausting 1918 space.


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