On Fri, Jan 21, 2022 at 10:46:35PM -0500, Greg Wooledge wrote: [...]
> Well, yes. The "hostname" command sets the current hostname, which resides
> in memory only. It has no permanent effect.
>
> And it has nothing at all to do with IP addresses. Or DNS.
[...]
> Routing has nothing to do with your system's hostname. At all.
This is so important that it bears repeating. A couple of times :)
Hostname is a host's notion of its own host name. This can be different
from the name (or names) assigned to its IP addresses by the DNS. A
machine can have zero or IP addresses, and each of those can be known by
zero or more names in the DNS. Heck, several parts of a "split" DNS
world can disagree among them as to which names those IP addresses are
known by.
Of course, giving a host a name unrelated to (some of its) DNS names is
a bad idea in general, because it tends to confuse the heck out of
sysadmins (and in some case of applications: notably, SMTP servers
answer with "Hey, I'm patrick" (using the own hostname [1]): the server
at the other end will run away if it thinks it was talking to peter.
Cheers
[1] Unless you go to some lenghts to configure your SMTP server
otherwise.
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