I need to modify the file /etc/httpd/conf.d/phpMyAdmin.conf
in order to allow remote users (not only localhost) to login
# phpMyAdmin - Web based MySQL browser written in php
#
# Allows only localhost by default
#
# But allowing phpMyAdmin to anyone other than localhost should be considered
# dangerous unless properly secured by SSL
Alias /phpMyAdmin /usr/share/phpMyAdmin
Alias /phpmyadmin /usr/share/phpMyAdmin
<Directory /usr/share/phpMyAdmin/>
<IfModule mod_authz_core.c>
# Apache 2.4
<RequireAny>
Require ip 127.0.0.1
Require ip ::1
</RequireAny>
</IfModule>
<IfModule !mod_authz_core.c>
# Apache 2.2
Order Deny,Allow
Deny from All
Allow from 127.0.0.1
Allow from ::1
</IfModule>
</Directory>
<Directory /usr/share/phpMyAdmin/setup/>
<IfModule mod_authz_core.c>
# Apache 2.4
<RequireAny>
Require ip 127.0.0.1
Require ip ::1
</RequireAny>
</IfModule>
<IfModule !mod_authz_core.c>
# Apache 2.2
Order Deny,Allow
Deny from All
Allow from 127.0.0.1
Allow from ::1
</IfModule>
</Directory>
# These directories do not require access over HTTP - taken from the original
# phpMyAdmin upstream tarball
#
<Directory /usr/share/phpMyAdmin/libraries/>
Order Deny,Allow
Deny from All
Allow from None
</Directory>
<Directory /usr/share/phpMyAdmin/setup/lib/>
Order Deny,Allow
Deny from All
Allow from None
</Directory>
<Directory /usr/share/phpMyAdmin/setup/frames/>
Order Deny,Allow
Deny from All
Allow from None
</Directory>
# This configuration prevents mod_security at phpMyAdmin directories from
# filtering SQL etc. This may break your mod_security implementation.
#
#<IfModule mod_security.c>
# <Directory /usr/share/phpMyAdmin/>
# SecRuleInheritance Off
# </Directory>
#</IfModule>
The other answers so far seem to advocate the complete replacement of the <Directory/> block, this is not needed and may remove extra settings like the 'AddDefaultCharset UTF-8' now included.
To allow remote access you need to add 1 line to the 2.4 config block or change 2 lines in the 2.2 (depending on your apache version):
<Directory /usr/share/phpMyAdmin/>
AddDefaultCharset UTF-8
<IfModule mod_authz_core.c>
# Apache 2.4
<RequireAny>
#ADD following line:
Require all granted
Require ip 127.0.0.1
Require ip ::1
</RequireAny>
</IfModule>
<IfModule !mod_authz_core.c>
# Apache 2.2
#CHANGE following 2 lines:
Order Allow,Deny
Allow from All
Allow from 127.0.0.1
Allow from ::1
</IfModule>
</Directory>