Prevent access to Simple Mail Transfer Protocol ports

To secure your Simple Mail Transfer Protocol (SMTP) server from unknown applications, you might want to prevent access to SMTP ports.

To prevent access SMTP from starting and to prevent someone from associating a user application, such as a socket application, with the port that the iSeries™ server normally uses for SMTP, perform the following steps:
  1. In iSeries Navigator, expand your iSeries Server > Network > Servers > TCP/IP.
  2. Right-click TCP/IP Configuration and select Properties.
  3. In the TCP/IP Configuration Properties window, click the Port Restrictions tab.
  4. On the Port Restrictions page, click Add.
  5. On the Add Port Restriction page, specify the following settings:
    • User name: Specify a user profile name that is protected on your iSeries server. (A protected user profile is a user profile that does not own programs that adopt authority and does not have a password that is known by other users.) By restricting the port to a specific user, you automatically exclude all other users.
    • Starting port: 25
    • Ending port: 25
    • Protocol: TCP
  6. Click OK to add the restriction.
  7. On the Port Restrictions page, click Add and repeat the procedure for UDP.
  8. Click OK to save your port restrictions and close the TCP/IP Configuration Properties window. The port restriction takes effect the next time that you start TCP/IP. If TCP/IP is active when you set the port restrictions, you should end TCP/IP and start it again. The port restriction takes effect the next time that you start TCP/IP. If TCP/IP is active when you set the port restrictions, you should end TCP/IP and start it again.
Parent topic: Prevent Simple Mail Transfer Protocol access