Hello why in the Ports used by ISPConfig the Mysql port(3306) needs to be exposed to external connections? I would like to close it but i am not sure if would gonna cause any problems to ISPConfig....
MySQL has to listen on the external interface when you want to be able to configure access from outside like ISPConfig does. That's no problem as users are restricted to a specific IP anyway. If you have no users that use desktop MySQL tools or external servers, then you can configure it to listen on localhost only. The Ip based user configuration will not work then of course nor will multiserver setups work.
but once i've done tcp|in|d=3306|s=0.0.0.0 in csf.deny and bind-address=127.0.0.1 skip-networking in my.cnf the email client could not send message anymore... i do not understand once the email send and receive is done by the server itself by the remot email client software....
and in the mail.log that appeared Feb 2 14:35:00 vps postfix/proxymap[1802]: warning: connect to mysql server 127.0.0.1: Can't connect to MySQL server on '127.0.0.1' (111) Feb 2 14:35:00 vps postfix/trivial-rewrite[1804]: warning: virtual_mailbox_domains: proxy:mysql:/etc/postfix/mysql-virtual_domains.cf: table lookup problem Feb 2 14:35:00 vps postfix/trivial-rewrite[1804]: warning: virtual_mailbox_domains lookup failure Feb 2 14:35:00 vps postfix/trivial-rewrite[1804]: warning: virtual_mailbox_domains: proxy:mysql:/etc/postfix/mysql-virtual_domains.cf: table lookup problem Feb 2 14:35:00 vps postfix/trivial-rewrite[1804]: warning: virtual_mailbox_domains lookup failure Feb 2 14:35:00 vps postfix/smtpd[1874]: warning: connect to mysql server 127.0.0.1: Can't connect to MySQL server on '127.0.0.1' (111)
Remove the skip-networking. That's a deprecated setting and it instructs MySQL to not listen on 127.0.0.1.
is there anyway to block 3306 to external connections in a such way that email clients keeps allowed to send and receive?