SMTP (Simple Mail Transfer Protocol) is a protocol for e-mail transmission.
µC/SMTPc is an add-on product to µC/TCP-IP that implementing part of the following RFC:
RFC 2821: ftp://ftp.rfc-editor.org/in-notes/rfc2821.txt
This document describes how to configure and use the µC/SMTPc module in a µC/TCP-IP and µC/OS-II or µC/OS-III environment.