From: Tom Lane <tgl@sss.pgh.pa.us>
To: richard coleman <rcoleman.ascentgl@gmail.com>
cc: "David G. Johnston" <david.g.johnston@gmail.com>,
        Scott Ribe <scott_ribe@elevated-dev.com>,
        pgsql-admin <pgsql-admin@postgresql.org>
Subject: Re: postgresql definitive list of network resources used/needed?
In-reply-to: 
 <CAGA3vBv9gqzhCao9q4sLRWcRxDVHYuM0YHH91SqQCz-5T6RWkA@mail.gmail.com>
References: 
 <CAGA3vBstbWk88KvfJD0WzR89omKy9v+P_Z-S4p=_HC0g-xR58w@mail.gmail.com>
 <200DE464-2992-4D0C-96F1-6656E1CE932A@elevated-dev.com>
 <384610.1660168232@sss.pgh.pa.us>
 <CAGA3vBvvrbZNHRtfs+6DQtqJ3QRONaXhJAAooWmLm75j_F3U+A@mail.gmail.com>
 <CAKFQuwbjSOrUC3xQHxeTAcTys38s1yOCEA0Z9_N+xCkb0sMyjQ@mail.gmail.com>
 <CAGA3vBv9gqzhCao9q4sLRWcRxDVHYuM0YHH91SqQCz-5T6RWkA@mail.gmail.com>
Comments: In-reply-to richard coleman <rcoleman.ascentgl@gmail.com>
	message dated "Thu, 11 Aug 2022 09:17:50 -0400"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <484835.1660227202.1@sss.pgh.pa.us>
Date: Thu, 11 Aug 2022 10:13:22 -0400
Message-ID: <484836.1660227202@sss.pgh.pa.us>
Archived-At: 
 <https://www.postgresql.org/message-id/484836.1660227202%40sss.pgh.pa.us>
Precedence: bulk

richard coleman <rcoleman.ascentgl@gmail.com> writes:
> Is it correct to state that (barring the soon to be obsolete stats
> collector):

>    - PostgreSQL only uses the configured port, who's default is 5432, via
>    tcp
>    - outgoing connections are all tcp and use random ports

There are no outgoing connections in basic PG, unless maybe you
enable log_hostname, and then it'd depend on what your libc does
for DNS lookup --- but that'd more likely be UDP than TCP.

>    - none of the other intrinsic features; replication, pg_dump,
>    pg_basebackup, pg_restore, etc. use any other network ports

Replication surely requires some sort of connection, although it
could be either outgoing or incoming depending on your setup.
I'm also getting rather confused by what you mean by "use a port",
if you think that clients such as pg_dump don't.

>    - network ports used by extensions, even if included in the base
>    install, are beyond the scope of PostgreSQL documentation

If we were to start adding this sort of info to the docs,
it'd be appropriate to document the behavior of each included
extension in the documentation file for that extension.

As I go through these examples, though, I grow less enthusiastic
about it being a useful exercise at all.

			regards, tom lane