What is SSL and should I use it? What is SSL? SSL stands for Secure Sockets Layer. It is a protocol developed by Netscape for transmitting private documents via the Internet. SSL works by using a public key to encrypt data that's transferred over the SSL connection and is supported by any major browser. By convention, URLs that require an SSL connection start with https:// instead of http:// Using SSL with WebMail There are both advantages and disadvantages to using SSL with our webmail system. The primary reason to use it is to encrypt your WebMail sessions to ensure that no outsiders can intercept your email messages. The disadvantage is that when using SSL, data has to be encrypted and decrypted and sent over a secure channel, which is much slower than normal communication. In general most users are fine without having to enable SSL for WebMail purposes. If however, your email contains sensitive information, using SSL will provide an additional layer of security for you.