The Access List lets you set up certain IP address ranges which will either be rejected, analyzed, or relayed. You can change the order. As soon as the incoming IP matches a range, then matching will stop. If the incoming IP does not match any ranges, then the default processing will be used. The default processing is to analyze the message if the RCPT TO: of the e-mail matches a valid user/domain.
Analyze - This is the default, and would only need to be used if you needed to set up an ip address or IP range to analyze before an IP address or IP range you are rejecting or relaying.
Relay - This lets you set up a range of addresses from which e-mail will be relayed. Relaying will cause Spam Sleuth Enterprise to relay the message directly to the e-mail server without looking at the domain, or the contents. You should enter the range of your client computers if you install Spam Sleuth Enterprise on the same computer as your e-mail server, otherwise your e-mail clients will not be able to send e-mail without changes to the e-mail client configuration.
Reject - Spam Sleuth Enterprise will reject attempts to connect. You can use this to reject e-mail from blatant abusers of your e-mail system.