Allied Telesis AT-S60 - Manual (Page 382)

AT-S60 Management Software User’s Guide
Section III: Security Features 381
Secure Sockets Layer Overview
This chapter describes the Secure Sockets Layer (SSL) feature, a security
protocol that provides a secure and private TCP connection between a
client and server. You can configure the SSL feature using a local or
Telnet management session.
SSL can be used with many higher layer protocols including HTTP, File
Transfer Protocol (FTP) and Net News Transfer Protocol (NNTP). Most
web browsers and servers support SSL, and its most common
deployment is for secure connections between a client and server over
the Internet. The switch supports SSL versions 2.0 (client hello only) and
3.0 which were developed by Netscape, and the Internet Engineering
Task Force (IETF) standard for SSL, known as SSL version 3.1 or Transport
Layer Security (TLS).
Within the Ethernet protocol stack, SSL is a layer 4 protocol that is in
between the HTTP and TCP protocol layers. HTTP communicates with
SSL in the same way as with TCP. In other words, TCP processes SSL
requests like any other protocol requesting its services.
SSL provides a secure connection over which web pages can be
accessed from an HTTP server. The operation of SSL is transparent to the
end user who is accessing a web site with the following exceptions:
❑ the site’s URL changes from http to https
❑ the browser displays a padlock icon.
By default, HTTP and HTTPS use the separate well-known ports 80 and
443 respectively. Secure connections over the Internet are important
when transmitting confidential data such as credit card details or
passwords. SSL allows the client to verify the server’s identity before
either side sends any sensitive information. SSL also prevents a third
party from interfering with the message because only trusted devices
have access to the unprotected data.
SSL Encryption SSL uses encryption to ensure the security of data transmission.
Encryption is a process that uses an algorithm to encode data so it can
only be accessed by a trusted device. An encrypted message remains
confidential.