PostgreSQL has native support for using
SSL connections to encrypt client/server communications
for increased security. This requires
OpenSSL be installed on both client and
server systems and support enabled at build time (see Chapter 1).
With SSL support compiled in, the
PostgreSQL server can be started with
SSL support by setting the parameter
ssl to on in postgresql.conf. When
starting in SSL mode, the server will look for the
files server.key and server.crt in the
data directory. These files should contain the server private key
and certificate respectively. These files must be set up correctly
before an SSL-enabled server can start. If the private key is
protected with a passphrase, the server will prompt for the
passphrase and will not start until it has been entered.
The server will listen for both standard and SSL
connections on the same TCP/IP port, and will negotiate with any
connecting client on whether to use SSL. See Chapter 6 about how to force the server to
require use of SSL for certain connections.
For details on how to create your server private key and certificate,
refer to the OpenSSL documentation. A simple
self-signed certificate can be used to get started for testing, but a
certificate signed by a certificate authority (CA) (either one of the global
CAs or a local one) should be used in production so the
client can verify the server's identity. To create a quick
self-signed certificate, use the following
OpenSSL command:
openssl req -new -text -out server.req
Fill out the information that openssl asks for. Make sure
that you enter the local host name as Common Name; the challenge
password can be left blank. The script will generate a key that is
passphrase protected; it will not accept a passphrase that is less
than four characters long. To remove the passphrase (as you must if
you want automatic start-up of the server), run the commands
openssl rsa -in privkey.pem -out server.key
rm privkey.pem
Enter the old passphrase to unlock the existing key. Now do
openssl req -x509 -in server.req -text -key server.key -out server.crt
chmod og-rwx server.key
to turn the certificate into a self-signed certificate and to copy the
key and certificate to where the server will look for them.
