POP3

• Enable Service - This controls whether the service is enabled.
• Port - This controls which port the service will listen on. It is recommended that you keep the default value of 110 as this is the standard POP3 port.
• Max Connections - This controls the maximum number of simultaneous connections the service will allow. It is recommended that this value be no higher than 200.
• Idle Timeout - If a connection remains idle, this value will control the period of time before the connection is forcefully shutdown.
• Use Server Default - If selected, this will bind the ports to the IPs specified by the Server Admin Settings.
• Bind to All Available IPs - If selected, this will bind the ports to all available IPs.
• Listen Only on IP(s) - If selected, this will bind the port to the IPs listed here. To set multiple IPs, simply separate each IP with a semi-colon (‘;’). Also, it is acceptable to specify a domain name instead of an IP.
• Use Explicit SSL - This allows incoming connections to use the STLS command to initiate a secure TLS connection.
• Use SSL Version 2/3 Mode With TLS - Some email clients do not fully support TLS version 1, so to help compatibility this option enables the use of SSL version 2/3 in place of TLS version 1.
• Use Implicit SSL - This allows a secondary dedicated port for secure SSL connections to be opened. The implicit SSL port will also be affected by all the normal port bindings and limits.
• SSL Port - This controls which port the SSL part of the service will listen on. It is recommended that you keep the default value of 995 as this is the standard POP3 SSL port.
• Certificate - This option controls which SSL certificate will be used for SSL sessions. For more information on how to edit the SSL certificates please view the SSL Certificates page.
• Enable Anti-Hammering - Enabling this option will protect the service against brute force password guessing attacks. If an IP performs too many login failures, that IP will be blocked for a set period of time. For more information please view the Server Admin Settings page.

IP Control

• Enable IP Black List - If enabled, the IPs and IP ranges in the list box will be blocked from accessing the service.
• Enable IP White List - If enabled, the IPs and IP ranges in the list box will always be allowed access to the service. This protection overrules blocked IPs but does not overrule Anti-Hammering.