On some OSes, it might be useful to set up mysql/mariadb/percona with the "skip-name-resolve" option.

But this breaks nearly everything in ISPConfig.

It would be great to update install script (and probabily others scripts) to replace "localhost" by "127.0.0.1", because even if this option is not setted, "127.0.0.1 = localhost" while "localhost not necessarily equal to 127.0.0.1" (for mysql)