The Enable Service box lets you enable or disable the service. This service is usually disabled because it is generally considered insecure.
The Bindings section is described in the Service Bindings topic.
Bandwidth Throttling allows you to set limits on how fast data will be transferred through this SMTP service. This allows you to prevent it taking up all your available bandwidth. See the Bandwidth Throttling topic for more information.
The Finger protocol returns text - in either a verbose or normal response. The administrator can define a template which defines the text returned. The template can contain plain text,with some tags (defined as displayed below the template box - eg <id> for the account name).