ALMA-09-019490 - AlmaLinux OS 9 must be configured to prevent unrestricted mail relaying.

Information

If unrestricted mail relaying is permitted, unauthorized senders could use this host as a mail relay for the purpose of sending spam or other unauthorized activity.

Solution

Modify the postfix configuration file to restrict client connections to the local network with the following command:

$ postconf -e 'smtpd_client_restrictions = permit_mynetworks,reject'

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_CL_AlmaLinux_OS_9_V1R5_STIG.zip

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-269252r1050134_rule, STIG-ID|ALMA-09-019490, Vuln-ID|V-269252

Plugin: Unix

Control ID: 2eda406cfc8323443352783d0bf353c527484d83b46110238be04972aed8ebf7