|PostgreSQL Reference Manual - Volume 3 - Server Administration Guide|
by The PostgreSQL Global Development Group
Paperback (6"x9"), 204 pages
RRP £13.95 ($24.95)
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3.7 Secure TCP/IP Connections with SSL
PostgreSQL has native support for using SSL connections to encrypt client/server communications for increased security. This requires that OpenSSL is installed on both client and server systems and that support in PostgreSQL is enabled at build time (see section 1 Installation Instructions).
With SSL support compiled in, the
PostgreSQL server can be started with
SSL enabled by setting the parameter
starting in SSL mode, the server will look for the
files ‘server.key’ and ‘server.crt’ in the
data directory, which must 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 port, and will negotiate with any connecting client on whether to use SSL. By default, this is at the client's option; see section 7.1 The pg_hba.conf file about how to set up the server to require use of SSL for some or all connections.
For details on how to create your server private key and certificate, refer to the OpenSSL documentation. A self-signed certificate can be used 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 program 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.
If verification of client certificates is required, place the certificates of the CA(s) you wish to check for in the file ‘root.crt’ in the data directory. When present, a client certificate will be requested from the client during SSL connection startup, and it must have been signed by one of the certificates present in ‘root.crt’. Certificate Revocation List (CRL) entries are also checked if the file ‘root.crl’ exists.
When the ‘root.crt’ file is not present, client certificates will not be requested or checked. In this mode, SSL provides communication security but not authentication.
The files ‘server.key’, ‘server.crt’, ‘root.crt’, and ‘root.crl’ are only examined during server start; so you must restart the server to make changes in them take effect.
|ISBN 0954612043||PostgreSQL Reference Manual - Volume 3 - Server Administration Guide||See the print edition|