need details on port 4190:sieve

Hi, it is unclear to me if an open 4190 on a single server setup is really needed?
My setup is just for email and Roundcube isn't installed either, for better understanding i installed:

Code:

wget -O - https://get.ispconfig.org | sh -s -- --no-dns --use-unbound --no-roundcube --no-pma --no-mailman --no-quota --unattended-upgrades=autoclean,reboot --monit [email protected]  --ssh-port=xxx --ssh-permit-root=no --ssh-password-authentication=no --ssh-harden --interactive --use-php=system

QUESTION 1:
From what i gather i could config dovecot.conf to allow sieve only accept local connections but i am unclear if,
1) i should in my setup scenario and 2) neither do i know how correctly disable external connection except by blocking the port via ufw/fw


QUESTION 2:
About MariaDB to only listen to local ports, whats the current way?
Removing 3306 from default allowed ufw ports setup and also wanted to make sure that mariaDB is only listening to local ports but run into errors, see below.

Code:

 vim /etc/mysql/mariadb.conf.d/50-server.cnf 

and removed the remark from,

Code:

 bind-address            = 127.0.0.1 

But i do see

Code:

[Warning] Aborted connection 1627 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication) 

in the logs.
Tried with,

Code:

 bind-address            = 127.0.0.1,127.0.1.1 

but then web UI wasn't working anymore.

 

Safety precaution, what am i not understanding here, if you please would be so kind to elaborate why i would need the port to be accessible from the outside world with my setup?

PS
I do still see the,

Code:

 [Warning] Aborted connection 3926 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication) 

after remarking the bind to localhost back to original setting. Only the port is blocked by ufw now.

 

Ok, as i have it right now.
What can you tell me about this warning i see in syslog, what is trying to authenticate exactly every minute two times and fails both?

Code:

~# mariadb --version
mariadb  Ver 15.1 Distrib 10.6.12-MariaDB, for debian-linux-gnu (x86_64) using  EditLine wrapper
~# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 22.04.2 LTS
Release:        22.04
Codename:       jammy