HS SMTP

In order to support the ever increasing usage of e-mailing over TCP networks, there are some standard protocols for e-mail servers such as SMTP, IMAP, POP3 etc, to name a few. These protocols are the standards which an e-mail client should support for sending as well as receiving e-mails. SMTP (Simple Mail Transfer Protocol) is one standard protocol. In order to do e-mailing through this protocol, your email client should support transfer of mails through it. If you are a programmer or a developer, you require a software library for developing such an application in a simplified manner. HS SMTP v.2.0.3 is a complete package for such purposes.

HS SMTP by HillStone Software is a software library for SMTP supporting e-mail client. It works in widely used programming language C with a detailed library of source codes. The e-mails are transferred over TCP socket layer and it supports transfer of text and message header over this protocol. The layout of the user application contains various fields for information about the sender, receiver, cc, bcc, subject and text body which is quiet familiar for an average user. Apart from this, you can also attach files like any conventional e-mail clients. The client application calls a function HsSmtpSendMail with information about IP address or name of the respective mail server, sender and recipient`s address, subject etc and also calls reverse function for information about the process and any underlying server errors for mail transfer. The source code library then proceeds with resolution of name of server and transmits message via SMTP RFC 821.

Overall, HS SMTP v.2.0.3 is a detailed source code library for user application to support transfer of e-mails under the SMTP protocol. Hence, it receives a score of four-and-a-half rating points on the scale of five.

HS SMTP is a software library in C (supplied with full source code) which implements the client side of Simple Mail Transfer Protocol (SMTP) over TCP socket layer according to RFC 821. Support for transfer of basic message header and text is provided
From version 1.1, HS SMTP supports ESMTP extension for LOGIN Authentication using Base64 encoding and message sending to multiple recipients from address list.
From version 1.2 HS SMTP supports sending binary file attachments using MIME version 1.0 base64 encoding
From version 2.0.0 HS SMTP supports secure SMTP over TLS / SSL (RFC 3207)
To send a text email message to any address on the internet, the user application calls a single function HsSmtpSendMail, specifying mail server name or IP address, sender address, recipient address, message text buffer and length, subject, cc and an event callback function to use for reporting of operation result and server errors.
HS SMTP library then resolves the server name, connects to it and transmits the message according to SMTP RFC 821 protocol. HS SMTP Library incorporates the necessary state machine, transparency procedures, and server response processing required to comply to a simple and robust SMTP client implementation.
Modular design makes it easy to port HS SMTP protocol module to any environment. HS SMTP internally at a lower layer interfaces to HS Sock library which provides TCP transport services. User application need not worry about Winsock - HS SMTP does all transmission, reception and event handling over socket layer.
Features
-SMTP Client Operation
-Server name resolution
-Supports up to 5 contexts
-Message Header Transfer
-Message Text Transfer
-Asynchonous Operation
-Sending MIME base64 binary file attachments
-ESMTP Authentication
-Secure SMTP over TLS (RFC 3207)
* This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit