Red Hat Enterprise Linux 6 and its derivative CentOS 6 includes a graphical tool called Firewall Configuration for configuring the firewall options. This article describes how to use the Firewall Configuration tool to open up the ports necessary for providing an email server.
1. Click System, select Administration and click Firewall. This will launch the Firewall Configuration window.
2. Click Close in the Firewall Configuration Startup window.
3. Type in the root password and click Authenticate.
If the Firewall Configuration Startup window does not disappear after clicking Close, click the window behind it to bring the Authenticate window into the foreground.
4. In the service list, check Mail (SMTP) and WWW (HTTP).
5. Click Other Ports and click Add.
6. Select 110 tcp pop3 and click Ok. Do the same for 143 tcp imap.
7. Finally, click Apply to save your changes.
1. Launch the Firewall Configuration tool using the command below. 
2. In Firewall Configuration screen, press the Customize button.
3. In the service list, check Mail (SMTP) and WWW (HTTP). Press Forward when you are done.
4. Press Add to add a custom port.
5. Type in 110 to the field Port and tcp to the field Protocol. Press OK when you are done. Do the same for 143:tcp.
6. After adding the two ports press Close.7. Finally, press OK and press Yes to confirm overriding of firewall configuration. You can see the list of service and port numbers using the command below.
Firewall Configuration (GUI)
This section describes how to use the Firewall Configuration tool to configure the firewall.
1. Click System, select Administration and click Firewall. This will launch the Firewall Configuration window.
2. Click Close in the Firewall Configuration Startup window.
3. Type in the root password and click Authenticate.If the Firewall Configuration Startup window does not disappear after clicking Close, click the window behind it to bring the Authenticate window into the foreground.
4. In the service list, check Mail (SMTP) and WWW (HTTP).
5. Click Other Ports and click Add.
6. Select 110 tcp pop3 and click Ok. Do the same for 143 tcp imap.
7. Finally, click Apply to save your changes.Firewall Configuration (TUI)
This section describes how to use the Firewall Configuration text user interface (TUI) tool to configure the firewall.
1. Launch the Firewall Configuration tool using the command below. system-config-firewall-tui
2. In Firewall Configuration screen, press the Customize button.
3. In the service list, check Mail (SMTP) and WWW (HTTP). Press Forward when you are done.
4. Press Add to add a custom port.
5. Type in 110 to the field Port and tcp to the field Protocol. Press OK when you are done. Do the same for 143:tcp.
6. After adding the two ports press Close.7. Finally, press OK and press Yes to confirm overriding of firewall configuration.You can see the list of service and port numbers using the command below. getent services
No comments:
Post a Comment