Provides SMTP STARTTLS support for Ruby 1.8.6 (built-in for 1.8.7+). Simply require 'smtp_tls' and use the Net::SMTP#enable_starttls method to talk to servers that use STARTTLS. require 'net/smtp' begin require 'smtp_tls' rescue LoadError end smtp = Net::SMTP.new address, port smtp.enable_starttls smtp.start Socket.gethostname, user, password, authentication do |server| server.send_message message, from, to end You can also test your SMTP connection settings using mail_smtp_tls: $ date | ruby -Ilib bin/mail_smtp_tls smtp.example.com submission \ "your username" "your password" plain \ from@example.com to@example.com Using SMTP_TLS 1.0.3 -> "220 smtp.example.com ESMTP XXX\r\n" <- "EHLO you.example.com\r\n" -> "250-smtp.example.com at your service, [192.0.2.1]\r\n" -> "250-SIZE 35651584\r\n" -> "250-8BITMIME\r\n" -> "250-STARTTLS\r\n" -> "250-ENHANCEDSTATUSCODES\r\n" -> "250 PIPELINING\r\n" <- "STARTTLS\r\n" -> "220 2.0.0 Ready to start TLS\r\n" TLS connection started <- "EHLO you.example.com\r\n" -> "250-smtp.example.com at your service, [192.0.2.1]\r\n" -> "250-SIZE 35651584\r\n" -> "250-8BITMIME\r\n" -> "250-AUTH LOGIN PLAIN\r\n" -> "250-ENHANCEDSTATUSCODES\r\n" -> "250 PIPELINING\r\n" <- "AUTH PLAIN BASE64_STUFF_HERE\r\n" -> "235 2.7.0 Accepted\r\n" <- "MAIL FROM:<from@example.com>\r\n" -> "250 2.1.0 OK XXX\r\n" <- "RCPT TO:<to@example.com>\r\n" -> "250 2.1.5 OK XXX\r\n" <- "DATA\r\n" -> "354 Go ahead XXX\r\n" writing message from String wrote 91 bytes -> "250 2.0.0 OK 1247028988 XXX\r\n" <- "QUIT\r\n" -> "221 2.0.0 closing connection XXX\r\n" This will connect to smtp.example.com using the submission port (port 587) with a username and password of "your username" and "your password" and authenticate using plain-text auth (the submission port always uses SSL) then send the current date to to@example.com from from@example.com. Debug output from the connection will be printed on stderr.