On Tue, Mar 9, 2021 at 10:10 PM Grant Taylor <
gtaylor@gentoo.tnetconsulting.net> wrote:
>
> On 2/21/21 3:23 PM, Grant Taylor wrote:
> > Will someone please explain why the Gentoo AMD64 Handbook ~> Gentoo (at
> > large) says to add the local host name to the 127.0.0.1 (or ::1) entry
> > in the /etc/hosts file?  What was the thought process behind that?
>
> Shameless Bump  --  I'm still interested in understanding the logic
> behind the choice in the Gentoo Handbook.
>
> Additional information.
>
> The Samba Wiki states the following in the Preparing the Installation
> section of the Setting up Samba as an Active Directory Domain Controller
> document.
>
> "The host name and FQDN must not resolve to the 127.0.0.1 IP address or
> any other IP address than the one used on the LAN interface of the DC."
>
> Link - Setting up Samba as an Active Directory Domain Controller -
> Preparing the Installation
>   -
>
https://wiki.samba.org/index.php/Setting_up_Samba_as_an_Active_Directory_Domain_Controller#Preparing_the_Installation
>

AND

[quote]
I'm reading Kerberos - The Definitive Guide[1] and it makes the
following comment:

> And to make matters worse, some Unix systems map their own hostname
> to 127.0.0.1 (the loopback IP address).
[/quote]

Caveat - not an expert, just my meager understanding:

1) The name 'localhost' is historically for developers who want to access
their own machine _without_ using DNS.

2) By general practice sometime in the deep, dark times 127.0.0.1 was
accepted for this purpose. There's nothing special about the address.

3) I read the original quoted comment in the Kerberos Guide as a warning -
'to make matters worse, __SOME__"

4) In my /etc/hosts I do _NOT_ map my machine's name to the same address as
localhost, avoiding the Kerberos warning:

mark@science:~$ cat /etc/hosts
127.0.0.1       localhost
127.0.1.1       science

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

mark@science:~$ ping localhost
PING localhost (127.0.0.1) 56(84) bytes of data.
64 bytes from localhost (127.0.0.1): icmp_seq=1 ttl=64 time=0.032 ms

mark@science:~$ ping science
PING science (127.0.1.1) 56(84) bytes of data.
64 bytes from science (127.0.1.1): icmp_seq=1 ttl=64 time=0.032 ms

mark@science:~$ hostname
science
mark@science:~$ hostname -I
192.168.86.42
mark@science:~$ hostname -A
science.lan
mark@science:~$ hostname -f
science
mark@science:~$ hostname -i
127.0.1.1
mark@science:~$