To install PostgreSQL, run the following command in the command prompt:

sudo apt-get install postgresql

Once the installation is complete, you should configure the PostgreSQL server based on your needs, although the default configuration is viable.

By default, connection via TCP/IP is disabled. PostgreSQL supports multiple client authentication methods. By default, IDENT authentication method is used for postgres and local users. Please refer the PostgreSQL Administrator's Guide.

The following discussion assumes that you wish to enable TCP/IP connections and use the MD5 method for client authentication. PostgreSQL configuration files are stored in the /etc/postgresql/<version>/main directory. For example, if you install PostgreSQL 8.4, the configuration files are stored in the /etc/postgresql/8.4/main directory.

To enable TCP/IP connections, edit the file /etc/postgresql/8.4/main/postgresql.conf

Locate the line #listen_addresses = 'localhost' and change it to:

listen_addresses = 'localhost'

You may also edit all other parameters, if you know what you are doing! For details, refer to the configuration file or to the PostgreSQL documentation.

Now that we can connect to our PostgreSQL server, the next step is to set a password for the postgres user. Run the following command at a terminal prompt to connect to the default PostgreSQL template database:

sudo -u postgres psql template1

The above command connects to PostgreSQL database template1 as user postgres. Once you connect to the PostgreSQL server, you will be at a SQL prompt. You can run the following SQL command at the psql prompt to configure the password for the user postgres.

ALTER USER postgres with encrypted password 'your_password';

After configuring the password, edit the file /etc/postgresql/8.4/main/pg_hba.conf to use MD5 authentication with the postgres user:

local   all         postgres                          md5

Finally, you should restart the PostgreSQL service to initialize the new configuration. From a terminal prompt enter the following to restart PostgreSQL:

sudo /etc/init.d/postgresql-8.4 restart