Does AuthSMTP use POP-before-SMTP?

No. POP-before-SMTP is another a method of authenticating users - we have found it to be unreliable and have potential security issues so we use SMTP authentication instead.

POP-before-SMTP relaying relies on your email client collecting email (via POP / POP3) - it then notes your Internet IP address and allows that IP address to send mail through the server for a certain amount of time (typically around 30-60 minutes).

The problems with this are:

  • Some email programs do not collect mail first or send and receive at the same time - this then can result in your email not sending or returning with'relaying denied' errors.
  • If you only send mail (many email programs will send email immediately as they are created) it may not send and return with 'relaying denied'errors.
  • Not everyone uses POP / POP3 to collect their mail - many people use IMAP or other email systems and SMTP to send mail.
  • Security (part 1) - if you disconnect from the Internet (dial-up) or your ISP changes your IP address (broadband) someone else may be allocated your IP address and (although fairly unlikely) 'could' send mail out on your POP-before-SMTP account.
  • Security (part 2) - some Internet connections (for instance NAT or SOCKS proxied) 'share' one IP address among multiple local users. Often this is just between users at the same company - this is not always the case - again this could mean other users could relay mail out using your account!

So why use POP-before-SMTP when our AuthSMTP 'authenticated SMTP' service does not suffer from these problems and is available for such a low cost.