You can block electronic mail based upon any of the following criteria:

• The From: address or domain name
• The Envelope-From: address or domain name
• IP Number
• Host Name
• Ident information
• Recipient address or domain name
• Subject: content
• Message body content
• Message headers content

Usually, you can enter in a domain name or address and MailBlock will automatically determine what you meant. However, such advanced features as wildcards and regular expressions can allow you to gain even more control over your block lists.