Skip to main content

logo email instellen nl

When do I use SSL and when STARTTLS for email?

It is important for all e-mail you send to be sent securely. You can do this by using so-called encryption (also called encryption) while sending but also while receiving. This prevents email that is intercepted from being read by other parties.

You can either encrypt the content of the email or the sending of email. In this explanation, we are talking about encrypting the sending of email using the SSL or TLS transfer protocol. TLS (Transport Layer Security) is better known as SSL (Secure Socket Layer) which is the old name.

SSL, TLS and STARTTLS, what are the differences?

SSL is not new, it has been around since around 1994 with version 1.0 never appearing on the market and version 2.0 quickly being replaced by version 3.0 due to weaknesses in the cryptography. Meanwhile, since 2014, version 3.0 must also be considered insecure.

TLS has been developed since 1999 and has reached version 1.3 as of 2018. TLS is based on Secure Socket Layer (SSL). TLS is also more secure than SSL on many fronts and is therefore preferred.

What to look out for,

In any case, it is important that you prefer to use STARTTLS as your encryption method and do not send or receive your e-mail unsecured. Also make sure you use an up-to-date mail programme because if it is too old, it does not support recent versions of security. This can become a problem, sometimes causing your e-mail not to arrive or possibly to be returned.

A summary (not 100 per cent complete) for inspiration:


TLS versie1.
Office 365 As of October 2018, TSL 1.0 and TSL 1.1 are no longer supported.
Outlook 2003 There is no support for TLS, find a newer mail programme if you want to mail securely.
Gmail Gmail uses a recent version and updates it whenever possible.