Attachments that are sent and received should be completely and thoroughly checked for viruses. When a virus is discovered, different products deal with it in different ways. Others place it into a quarantined area, so that the administrator can decide whether the message and attached file should be cleaned manually and then allowed through. The recent e-mail virus scares have centered around Visual Basic Script files that have a .VBS extension, although you should also be wary of some other formats. Address blocking allows you to create filters that prevent unwanted e-mail from being delivered to your system.
Filters often have the ability to use wildcards to create a comprehensive blocking strategy.
In addition, some products make use of centralised lists of spammers that can be downloaded and used by the content-vetting software. Restricting the size of the attachments that can be sent and received protects your valuable bandwidth, potentially saving costs in the meantime. Filters can be configured that will prevent mails of an abusive, racist, sexual, or discriminatory nature. Another potential feature of content blocking is the prevention of company information from being e-mailed to other parties. You could, for example, block mails that contain a character string that relates to a current project or product.