Puppet Class: cis_security_hardening::rules::mta_local

Defined in:
manifests/rules/mta_local.pp

Summary

Ensure mail transfer agent is configured for local-only mode

Overview

Mail Transfer Agents (MTA), such as sendmail and Postfix, are used to listen for incoming mail and transfer the messages to the appropriate user or mail server. If the system is not intended to be a mail server, it is recommended that the MTA be configured to only process local mail.

Rationale: The software for all Mail Transfer Agents is complex and most have a long history of security issues. While it is important to ensure that the system can process local mail messages, it is not necessary to have the MTA’s daemon listening on a port unless the server is intended to be a mail server that receives and processes mail from other systems.

Examples:

class { 'cis_security_hardening::rules::mta_local':
    enforce => true,
}

Parameters:

  • enforce (Boolean) (defaults to: false) —

    Enforce the rule



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# File 'manifests/rules/mta_local.pp', line 23

class cis_security_hardening::rules::mta_local (
  Boolean $enforce = false,
) {
  if  $enforce and
  fact('cis_security_hardening.postfix') == 'yes' {
    file_line { 'mta-loca-config':
      path     => '/etc/postfix/main.cf',
      line     => 'inet_interfaces = loopback-only',
      match    => 'inet_interfaces\s*=',
      multiple => true,
      notify   => Exec['restart postfix'],
    }

    exec { 'restart postfix':
      command     => 'systemctl restart postfix',
      path        => ['/bin', '/usr/bin', '/sbin', '/usr/sbin'],
      refreshonly => true,
    }
  }
}