Ubuntu – Can’t connect to postgresql on local machine using IP + pgadmin

The answer from DerfK above is wrong. You can use PostgreSQL using Unix socket with roundcube provided you're configuring it well. In the db.inc.php, it should read:

$rcmail_config['db_dsnw'] = 'pgsql://roundcube:*password*@unix(/tmp)/roundcube';

Provided you've created a "roundcube" user in pgsql for the database "roundcube" with password "password" In your main postgresql.conf, you should prevent listening on the IP layer, by changing:

listen_addresses = ''
unix_socket_directory = '/tmp'
ssl = false  # There's no point in using SSL on a local UNIX socket except wasting CPU

Also, and that is the most important part, you must change in pg_hba.conf to add this line:

local   all         roundcube                        md5

Restart everything, and it's working perfectly well and faster than using TCP connections (since you avoid all the IP encapsulation).

Have you set up phppgadmin in the lighty config?

alias.url = ("/pgadmin" => "/usr/share/phpPgAdmin")

You also have to enable mod_alias in Lighty (and restart it) and then "http://localhost/pgadmin" should work ...