====== Network Services Overview SMTP ======

**General Information**

This page covers the Network Services objectives, specifically for SMTP. 

**Network Services Objectives**
  * Install the packages needed to provide the service
  * Configure SELinux to support the service
  * Use SELinux port labeling to allow services to use non-standard ports
  * Configure the service to start when the system is booted
  * Configure the service for basic operation
  * Configure host-based and user-based security for the service

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====== Lab Setup ======

The following virtual machines will be used:
  * server1.example.com (192.168.1.150) -> Configure SMTP null client (**on the exam**)
  * server2.example.com (192.168.1.151) -> Configure central mail server for client testing (**NOT on the exam**)

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====== Install the packages needed to provide the service ======

Install the service
<code bash>
yum install postfix
</code>

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====== Configure SELinux to support the service ======

  * Service agnostic -> [[linux_wiki:set_enforcing_and_permissive_modes_for_selinux|Ensure SELinux is running and enabled (RHCSA objective)]].

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====== Use SELinux port labeling to allow services to use non-standard ports ======

Configuring the <service-name> with a non standard port and allowing port access with selinux.

**NOTE**: "man semanage-port" has examples for allowing non-standard ports!

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====== Configure the service to start when the system is booted ======

Check Current Service Status
<code bash>
systemctl status postfix
</code>
  * Also displays if the service is enabled or disabled

\\
Enabling a service to start on boot
<code bash>
systemctl enable postfix
</code>

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====== Configure the service for basic operation ======

Enable and Start the service
<code bash>
systemctl enable postfix
systemctl start postfix
</code>

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====== Configure host-based and user-based security for the service ======

===== Firewall =====

Allow access through the firewall
<code bash>
firewall-cmd --permanent --add-service=smtp
firewall-cmd --reload
</code>

===== Host Based =====


===== User Based =====

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