Issue
I followed the standard installation of iRedMail (Version 1.4.2) and updated the SSH certificates following this guide: href="https://www.linuxbabe.com/mail-server/debian-10-buster-iredmail-email-server" rel="nofollow noreferrer">https://www.linuxbabe.com/mail-server/debian-10-buster-iredmail-email-server
After a succefull installation some of my services (such as an Express REST API) couldn't be reached anymore because the assigned Port was blocked.
I checked iptables
and ufw
setup and disabled ufw all together aswell but nothing changed.
I also looked at every log from each service that got installed with iRedMail and tried some configurations with nginx
to proxy_serve that port.
Nothing seemed to be working and it wasn't specifically bound to that port aswell (any port which wasn't related to Http, Https, smpt and so on did not work).
Solution
I found in a forum about fail2ban that nft
could be the problem.
For some reason the nft
firewall blocked every port.
Executing sudo nft flush ruleset
will remove every rule from nft and solved my problem.
I searched hours to find this solution, so I figured I should share it here.
Answered By - Scorix Answer Checked By - Mary Flores (WPSolving Volunteer)