Electronic mail is a valuable service which allows users to send and receive messages across networks. On most versions of Berkeley-derived Unix systems, the sendmail program is used to enable the receipt and delivery of mail. Older versions of sendmail have several bugs that allow security violations.
A few precautions can be taken to ensure secure operation of sendmail. These precautions are discussed in section 10.2.4 The UNIX mail command understands UUCP-style addressing. For information on using UUCP refer to sections 9.2.5 and 10.2.5.