RHEL 9 STIG Version Comparison

There are 86 differences between versions v2 r3 (Jan. 30, 2025) (the "left" version) and v2 r5 (July 2, 2025) (the "right" version).

Check RHEL-09-215101 was added to the benchmark in the "right" version.

This check's original form is available here.

Title

RHEL 9 must have the Postfix package installed.

Check Content

Verify that RHEL 9 has the Postfix package installed with the following command: $ sudo dnf list --installed postfix Example output: postfix.x86_64 2:3.5.25-1.el9 If the "postfix" package is not installed, this is a finding.

Discussion

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 such as 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

Fix

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