On Thu, Aug 27, 2020 at 09:51:49PM -0700, David G. Johnston wrote:
> On Thu, Aug 27, 2020 at 6:17 PM Tom Lane <[email protected]> wrote:
>
> PG Doc comments form <[email protected]> writes:
> > The following documentation comment has been logged on the website:
> > Page: https://www.postgresql.org/docs/9.5/ssh-tunnels.html
> > Description:
>
> > "The first number in the -L argument, 63333, is the port number of your
> end
> > of the tunnel; it can be any unused port. (IANA reserves ports 49152
> through
> > 65535 for private use.) The second number, 5432, is the remote end of
> the
> > tunnel: the port number your server is using. "
>
> > as a beginner This took me some time to understand what do you mean by
> "your
> > server" "your end of the tunnel "
>
> Hm, do you have a suggestion for better wording?
>
>
>
> I agree on the need for a different perspective here since it reads just fine
> once you know what it is talking about.
>
> But absent that maybe a slightly more tutorial flow would be good.
I didn't think a tutorial flow was the right thing to here, so I
reworded the section to be more details and have a clearer flow ---
patch attached.
--
Bruce Momjian <[email protected]> https://momjian.us
EnterpriseDB https://enterprisedb.com
The usefulness of a cup is in its emptiness, Bruce Lee
diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 6cda39f3ab..bc68ddc94b 100644
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -2548,34 +2548,39 @@ openssl x509 -req -in server.csr -text -days 365 \
First make sure that an <application>SSH</application> server is
running properly on the same machine as the
<productname>PostgreSQL</productname> server and that you can log in using
- <command>ssh</command> as some user. Then you can establish a secure
- tunnel with a command like this from the client machine:
+ <command>ssh</command> as some user; you then can establish a
+ secure tunnel to the remote server. A secure tunnel listens on a
+ local port and forwards all traffic to a port on the remote machine.
+ Traffic sent to the remote port can arrive on its
+ <literal>localhost</literal> address, or different bind
+ address if desired; it does not appear as coming from your
+ local machine. This command creates a secure tunnel from the client
+ machine to the remote machine <literal>foo.com</literal>:
<programlisting>
ssh -L 63333:localhost:5432 [email protected]
</programlisting>
The first number in the <option>-L</option> argument, 63333, is the
- port number of your end of the tunnel; it can be any unused port.
- (IANA reserves ports 49152 through 65535 for private use.) The
- second number, 5432, is the remote end of the tunnel: the port
- number your server is using. The name or IP address between the
- port numbers is the host with the database server you are going to
- connect to, as seen from the host you are logging in to, which
- is <literal>foo.com</literal> in this example. In order to connect
- to the database server using this tunnel, you connect to port 63333
- on the local machine:
+ local port number of the tunnel; it can be any unused port. (IANA
+ reserves ports 49152 through 65535 for private use.) The name or IP
+ address after this is the remote bind address you are connecting to,
+ i.e., <literal>localhost</literal>, which is the default. The second
+ number, 5432, is the remote end of the tunnel, e.g., the port number
+ your database server is using. In order to connect to the database
+ server using this tunnel, you connect to port 63333 on the local
+ machine:
<programlisting>
psql -h localhost -p 63333 postgres
</programlisting>
- To the database server it will then look as though you are really
+ To the database server it will then look as though you are
user <literal>joe</literal> on host <literal>foo.com</literal>
- connecting to <literal>localhost</literal> in that context, and it
+ connecting to the <literal>localhost</literal> bind address, and it
will use whatever authentication procedure was configured for
- connections from this user and host. Note that the server will not
+ connections by that user to that bind address. Note that the server will not
think the connection is SSL-encrypted, since in fact it is not
encrypted between the
<application>SSH</application> server and the
<productname>PostgreSQL</productname> server. This should not pose any
- extra security risk as long as they are on the same machine.
+ extra security risk because they are on the same machine.
</para>
<para>
@@ -2587,12 +2592,12 @@ psql -h localhost -p 63333 postgres
</para>
<para>
- You could also have set up the port forwarding as
+ You could also have set up port forwarding as
<programlisting>
ssh -L 63333:foo.com:5432 [email protected]
</programlisting>
but then the database server will see the connection as coming in
- on its <literal>foo.com</literal> interface, which is not opened by
+ on its <literal>foo.com</literal> bind address, which is not opened by
the default setting <literal>listen_addresses =
'localhost'</literal>. This is usually not what you want.
</para>
