pg_hba.conf location in Ubuntu 18.04

As a programmer working with PostgreSQL, it’s important to be familiar with the pg_hba.conf file, which controls client authentication to a PostgreSQL server. In Ubuntu 18.04, this file is located in the /etc/postgresql/<version>/main directory, where <version> corresponds to the version of PostgreSQL you have installed.

To access the pg_hba.conf file, you can simply cd to the directory where it’s located and open it using a text editor of your choice:

cd /etc/postgresql/<version>/main
sudo nano pg_hba.conf

Once you’ve opened the file, you’ll see entries that specify how client connections are authenticated. Each entry consists of a connection type (local, host, hostssl, or hostnossl), a database name or wildcard (all), a username or wildcard (all), and the authentication method (md5, password, peer, ident, pam, ldap, etc.).

Here's an example entry for allowing all local users to connect to all databases using a password:

# TYPE  DATABASE        USER            ADDRESS                 METHOD
host    all             all             127.0.0.1/32            md5

It’s important to configure the pg_hba.conf file correctly to ensure that only authorized clients can connect to your PostgreSQL server. Keep in mind that any changes to this file require a server restart to take effect.

Overall, familiarizing yourself with the location and contents of the pg_hba.conf file is an essential step in securing your PostgreSQL server.