HTTP | 80 | TCP | To be able to connect to operating system repositories who don't use https (Ubuntu) |
HTTPS | 443 | TCP | To be able to connect to package repository or bitbucket repository |
SMTP | usually 587 | TCP | To send email notifications, used port depends of your SMTP server configuration, usually 25/TCP, 587/TCP or 465/TCP |
DNS | 53 | UDP | To be able to resolve SMTP server name, or download.passbolt.com to check for updates |
NTP | 123 | UDP | To make server synchronized to a NTP server. Mandatory to make GPG or MFA/OTP work |
HKPS | 11371 | TCP | HKPS protocol for receiving GPG keys |