Date: Tue, 14 Aug 2018 15:18:03 -0500
From: Nico Williams <nico@cryptonector.com>
To: Garick Hamlin <ghamlin@isc.upenn.edu>
Cc: Fabien COELHO <coelho@cri.ensmp.fr>, Tom Lane <tgl@sss.pgh.pa.us>,
	PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Subject: Re: libpq should not look up all host addresses at once
Message-ID: <20180814201802.GE30604@localhost>
References: <4913.1533827102@sss.pgh.pa.us>
 <alpine.DEB.2.21.1808111122220.1705@lancre>
 <27728.1534189594@sss.pgh.pa.us>
 <alpine.DEB.2.21.1808132356130.2727@lancre>
 <20180814191832.GD6776@isc.upenn.edu>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20180814191832.GD6776@isc.upenn.edu>
User-Agent: Mutt/1.5.24 (2015-08-30)
Precedence: bulk

On Tue, Aug 14, 2018 at 03:18:32PM -0400, Garick Hamlin wrote:
> On Tue, Aug 14, 2018 at 12:24:32PM +0200, Fabien COELHO wrote:
> > I read the rational of the host/hostaddr artificial mapping. I cannot say
> > I'm thrilled with the result: I do not really see a setting where avoiding a
> > DNS query is required but which still needs a hostname for auth... If you
> > have GSSAPI or SSPI then you have an underlying network, in which a dns
> > query should be fine.
> 
> FWIW, I think this is useful even it will be uncommon to use.  I run
> some HA services here and I find I use this kind of functionality all
> the time to test if a standby node functioning properly.  openssh 
> GSSAPIServerIdentity does this.  curl does this via '--resolve'.  In
> both cases one can check the name authenticates properly via TLS or
> GSSAPI while connecting to an IP that is not production.  

+1

curl's --resolve is a fantastic diagnostic tool.  I wish it also allowed
changing the destination port as well.

While I'm at it, I strongly prefer using postgresql: URIs to any other
way to specify connect info, and I think PG should do more to encourage
their use -- perhaps even deprecating the alternatives.

Nico
--