The ancestor of sendmail, delivermail, also by Eric Allman, is a mail transport agent that used the FTP protocol on the early ARPANET to transmit e-mail to the recipient.[1] Due to deficiencies in using FTP to send e-mail, a new protocol was created in 1981 for sending e-mail, SMTP.[2] After DNS replaced hosts files, DNS-style host names were also adopted.[citation needed]

In 1979, when delivermail was first shipped with 4.0BSD and 4.1BSD, the ARPANET was still using NCP as its network protocol. When the ARPANET switched to TCP/IP at the end of 1982, the road was paved for MTAs which used TCP to deliver e-mail; delivermail evolved into sendmail.[citation needed]

References

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  1. ^ Sendmail, 3rd Edition by Bryan Costales, O'Reilly Media, Inc., 2002
  2. ^ "Simple Mail Transfer Protocol". Retrieved 2022-08-04.
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