All of these options are related to your Internet connection.
If port 995 (POP3) or port 993 (IMAP) is already being used by another program, you can choose another port here. Please change the port in your mail client, too.
Spamihilator is able to establish secure connections over SSL/TLS to your mail server. All data will be transferred in an encrypted format, so no one can read your mails or find out your passwords.
If this option is enabled, Spamihilator will check if your mail server supports secure connections when you connect to it the next time. If so, a secure connection will be established.
Allows you to manually specify which mail servers support SSL/TLS and which do not.