diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml index f975406acd..418aa3f85c 100644 --- a/doc/src/sgml/runtime.sgml +++ b/doc/src/sgml/runtime.sgml @@ -2611,34 +2611,39 @@ openssl x509 -req -in server.csr -text -days 365 \ First make sure that an SSH server is running properly on the same machine as the PostgreSQL server and that you can log in using - ssh as some user. Then you can establish a secure - tunnel with a command like this from the client machine: + ssh 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 + localhost 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 foo.com: ssh -L 63333:localhost:5432 joe@foo.com The first number in the 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 foo.com 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., localhost, 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: psql -h localhost -p 63333 postgres - 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 joe on host foo.com - connecting to localhost in that context, and it + connecting to the localhost 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 SSH server and the PostgreSQL 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. @@ -2650,12 +2655,12 @@ psql -h localhost -p 63333 postgres - You could also have set up the port forwarding as + You could also have set up port forwarding as ssh -L 63333:foo.com:5432 joe@foo.com but then the database server will see the connection as coming in - on its foo.com interface, which is not opened by + on its foo.com bind address, which is not opened by the default setting listen_addresses = 'localhost'. This is usually not what you want.