In a nutshell
The core of the Linux firewall is the netfilter kernel module. To add or remove firewall rules you need the "iptables" application (should already be installed).  where is the  [ ... ]

Backup the database

# mysqldump --opt -u username -p password -r mydb.dump mydb


Please note: Redirection does not capture UTF characters properly, while the -r option does (--result-file). I found this  [ ... ]