Why is 'localhost' the default host used when trying to connect to MariaDB? - host

Question

I have recently installed MariaDB on Fedora 19 in VirtualBox on Windows 7.
When I run:
MariaDB [(none)]> SELECT user, host, password FROM mysql.user;
I get:
+------+----------------------+-------------------------------------------+
| user | host | password |
+------+----------------------+-------------------------------------------+
| root | localhost | ***************************************** |
| root | my.hostname | ***************************************** |
| root | 127.0.0.1 | ***************************************** |
| nusr | my.hostname | ***************************************** |
+------+----------------------+-------------------------------------------+
my.hostname is the hostname I changed the default hostname to in Fedora.
I created the user 'nusr' with:
CREATE USER 'nusr'#'my.hostname' IDENTIFIED BY 'my_password';
When I try and connect to MariaDB with:
[me#my ~]$ mysql -u nusr -p
Enter password:
I get:
ERROR 1045 (28000): Access denied for user 'nusr'#'localhost' (using password: YES)
I am guessing this is because it is referring to 'nusr'#'localhost' instead of 'nusr'#'my.hostname'.
Why is 'localhost' the default host used when trying to connect to MariaDB?
Do the host's 'localhost' and '127.0.0.1' need to be kept?
As a context to this question, I am not really sure what the terms 'host' and 'hostname' mean, I just wanted to 'customise' my experience of learning MariaDB commands, so perhaps I have gone awry by completing the steps above.

Answer 1

Very old question but..
ERROR 1045 (28000): Access denied for user 'nusr'#'localhost' (using password: YES)
I am guessing this is because it is referring to 'nusr'#'localhost' instead of 'nusr'#'my.hostname'.
YES.
Why is 'localhost' the default host used when trying to connect to MariaDB?
Because the assumption is that you will connect to the database from the same machine the database is in (localhost).
If you define the user as being #my.hostname it means the connection to the database will be made from another machine, called my.hostname.
Do the host's 'localhost' and '127.0.0.1' need to be kept?
Only if you want to be able to access the database from there..
In that setup, if you delete root user #localhost and #127.0.0.1 then you will not be able to log into the database from inside the virtualbox where the database resides. And you will only be able to access if you connect from a machine called my.hostname. But for that to work you must make sure that the database environment knows my.hostname.

Answer 2

The MariaDB server (also MySQL) treats localhost in a special way. Where other software treat it like an alias of the loopback address 127.0.0.1, MariaDB will interpret it as a UNIX domain socket connection to the server. By default this socket file is located in /var/lib/mysql/mysql.sock.
To connect via the network to the local server, use the -h 127.0.01 parameter. This tells the mysql client to connect via the loopback network interface instead of the socket.
Regardless of other grants, MariaDB will always translate localhost to a local socket connection. If you want to prevent this and only allow access via the network, drop the users that have localhost as their host.
You can view all users in the database by executing the following query:
SELECT * FROM mysql.user

Answer 3

You must create properly user on system Fedora 19:
[root#localhost ~]# useradd nusr
[root#localhost ~]# passwd nusr
Changing password for user fedora.
New UNIX password:# set password
Retype new UNIX password:# confirm
passwd: all authentication tokens updated successfully.
[root#localhost ~]# exit # logout
So, a database didn't find user nusr and it will not to handle user nusr because isn't created on system wide.
Hostname is from IP address named as "mydomain.com", but "host" can be IP address or name lookup host "mydomain.com".