Re: [gentoo-user] Why do we add the local host name to the 127.0.0.1 / ::1 entry in the /etc/hosts file?

[Michael <confabulate@kintzios.com>]

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On Wednesday, 10 March 2021 16:00:19 GMT Mark Knecht wrote:
> <SNIP>
> 
> > mark@science:~$ cat /etc/hosts
> > 127.0.0.1       localhost
> > 127.0.1.1       science
> 
> <SNIP>
> <SNIP
> I think this is relevant to DNS resolution of/with domain controllers and
> may
> depend on the AD/DC topology.  The idea is to use the LAN address of the box
> as the first address in /etc/hosts and use 127.0.0.1 as the second address
> in
> the file.  If more AD/DNS servers exist in the network, then 127.0.0.1 could
> be even further down the list.
> 
> https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-se
> rver-2008-R2-and-2008/ff807362(v=ws.10)?redirectedfrom=MSDN
> 
> I haven't over-thought this and there may be more to it, but on a pure linux
> environment I expect this would not be a requirement, hence the handbook
> approach.
> <SNIP>
> 
> It could very well be but I have vague memories when I first started
> getting
> interested in Linux, circa 1996-97 with Redhat, that I would buy books that
> liberally sprinkled http://localhost or ping localhost sorts of lines in
> the text and
> examples.
> 
> My undocumented (and unsupported by data) opinion is that this localhost
> thing has been around a long, long time - possibly longer than Linux for
> all I know. Check out
> 
> http://acme.com
> 
> I have no real admin experience with any version of Windows. Even though
> I wrote, published and made a tiny bit of money selling a Windows program
> written in Turbo Pascal in those days I didn't even have networking.
> Everything was passed around on floppies.

I always thought the localhost class A addresses were from days of old 'inter-
network' era.  The difference with 127.0.0.1 and a private LAN address is the 
127.0.0.1 does not reach the data link layer, but loops-back at IP layer 3 and 
responds to any applications on the local PC.  So, I understood this to mean 
it never went through the whole network stack, as it does when you ping a 
remote host.

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