However, most of them involve an unnecessary SMTP server chain. This means that E-mail comes in to one SMTP server, is scanned for viruses, and then goes to another SMTP server which processes the mail in the usual fashion.
Some companies do a decent job at it, and charge a fortune.
Others do a lousy job, and charge a small fortune. Sometimes E-mail doesn't get scanned, if it is sent to local users. Sometimes E-mail doesn't get scanned, if authentication with the normal mail server is required. Declude Virus takes care of this problem by interacting with the mail server directly, and passing the attachments on to any command-line virus scanner of your choice. Since it communicates directly with the mail server, it bypasses that extra hop that causes so many problems.