AlmaLinux OS 9 must have the postfix package installed.

Severity
Group ID
Group Title
Version
Rule ID
Date
STIG Version
mediumV-272485SRG-OS-000304-GPOS-00121ALMA-09-006845SV-272485r1155265_rule2026-02-271

Description

Postfix is a free, open-source mail transfer agent (MTA) that sends and receives emails. It is a server-side application that can be used to set up a local mail server, create a null-client mail relay, use a Postfix server as a destination for multiple domains, or choose an LDAP directory instead of files for lookups. Postfix supports protocols like LDAP, SMTP AUTH (SASL), and TLS. It uses the Simple Mail Transfer Protocol (SMTP) to transfer emails between servers. Satisfies: SRG-OS-000304-GPOS-00121, SRG-OS-000343-GPOS-00134, SRG-OS-000363-GPOS-00150, SRG-OS-000447-GPOS-00201

ℹ️ Check

Note: If the admin can demonstrate that there is another system/service to send audit failure notifications to the administrator/ISSO, this control is not applicable. Verify AlmaLinux OS 9 has the postfix package installed with the following command: $ dnf list --installed postfix Example output: postfix.x86_64 2:3.5.9-24.el9 @AppStream If the "postfix" package is not installed, this is a finding.

✔️ Fix

Install the postfix package with the following command: $ sudo dnf install postfix