SSL - Secure Socket Layer


SSL is used for encryption perposes.   When people choose to use SSL, whether is be for Secure web browsing or sending emails.   You are comfirming identities of both parties to make sure all data is encrypted between the two.   For example all bank websites to view your online banking or any form of personal information will use SSL to encrypt data between the server and you so noone else can packet capture your personal information.


Some of the most common forms of SSL are used for


Web which is usually run by default on port 80 but for SSL purposes its run on 443.  Also when accessing websites which are using SSL they are not longer accessed by using HTTP:// instead you used HTTPS://  - note the addtional S for SSL

Another very common protocol using SSL would be mail.   These days it is pretty much a standard they your email is sent and received using SSL encyptoin.   By default SMTP runs on port 25 but when using SSL on SMTP you will use port 995 as default.