[ih] Origin of the loopback interface

[johnl at iecc.com (John Levine)]

In article <59EC70C6.2020809 at redbarn.org> you write:
>Brian Carpenter wrote:
>>>  So having a dedicated address for
>>>  loopback tests seems useless today.
>
>it's nowhere near useless. i use a some virtual machines that aren't on 
>any network except their loopback. grateful am i that i can use IP 
>sockets to talk to my own services ...

Even on machines that do have physical interfaces, puting a service
on a loopback address lets me be sure it's only available to other
processes on the same machine without having to screw around with
packet filters.  The usual example is a DNS cache.

It seems to me that having a single loopback address rather than at
least a /64 is one of the more inexplicable misfeatures of IPv6.

R's,
John