openssh unix dev - Feb 2021 - [openssh-commits] [openssh] 02/02: upstream: hostname is not specified by POSIX but uname -n is, so use

Chris Green wrote:
> Isn't it just 'hostname -f'?
> 
>     chris$ hostname -f
>     t470.zbmc.eu
>     chris$ hostname
>     t470
The hostname -f option is a "new-ish" Linux specific option.  It's
not
portable.  And because it works by doing a reverse DNS lookup it
depends upon live network connectivity at that moment working for the
network lookup and the results are spotty depending upon how DNS is
set up and how many IP addresses are configured on the host.

It's problematic.

Bob

On Mon, Feb 08, 2021 at 01:54:12PM -0700, Bob Proulx
wrote:
> Chris Green wrote:
> > Isn't it just 'hostname -f'?
> > 
> >     chris$ hostname -f
> >     t470.zbmc.eu
> >     chris$ hostname
> >     t470
> 
> The hostname -f option is a "new-ish" Linux specific option. 
It's not
> portable.  And because it works by doing a reverse DNS lookup it
> depends upon live network connectivity at that moment working for the
> network lookup and the results are spotty depending upon how DNS is
> set up and how many IP addresses are configured on the host.
> 
Yes, OK, just a thought.

-- 
Chris Green

On Mon, Feb 8, 2021 at 3:59 PM Bob Proulx <bob at proulx.com>
wrote:
>
> Chris Green wrote:
> > Isn't it just 'hostname -f'?
> >
> >     chris$ hostname -f
> >     t470.zbmc.eu
> >     chris$ hostname
> >     t470
>
> The hostname -f option is a "new-ish" Linux specific option. 
It's not
> portable.  And because it works by doing a reverse DNS lookup it
> depends upon live network connectivity at that moment working for the
> network lookup and the results are spotty depending upon how DNS is
> set up and how many IP addresses are configured on the host.
>
> It's problematic.
>
> Bob
It looks in /etc/hosts first, which works very well when DNS is
unavailable and when the host his publishing a dynamic DNS entry.