ZyXEL Communications Dimension ES-3148, User Manual, Page: 133 / 282

Dimension ES-3148 User’s Guide
Chapter 18 Access Control 131
The client automatically saves any new server public keys. In subsequent connections,
the server public key is checked against the saved version on the client computer.
2 Encryption Method
Once the identification is verified, both the client and server must agree on the type of
encryption method to use.
3 Authentication and Data Transmission
After the identification is verified and data encryption activated, a secure tunnel is
established between the client and the server. The client then sends its authentication
information (user name and password) to the server to log in to the server.
18.6 SSH Implementation on the Switch
Your switch supports SSH version 2 using RSA authentication and three encryption methods
(DES, 3DES and Blowfish). The SSH server is implemented on the switch for remote
management and file transfer on port 22. Only one SSH connection is allowed at a time.
18.6.1 Requirements for Using SSH
You must install an SSH client program on a client computer (Windows or Linux operating
system) that is used to connect to the switch over SSH.
18.7 Introduction to HTTPS
HTTPS (HyperText Transfer Protocol over Secure Socket Layer, or HTTP over SSL) is a web
protocol that encrypts and decrypts web pages. Secure Socket Layer (SSL) is an application-
level protocol that enables secure transactions of data by ensuring confidentiality (an
unauthorized party cannot read the transferred data), authentication (one party can identify the
other party) and data integrity (you know if data has been changed).
It relies upon certificates, public keys, and private keys.
HTTPS on the switch is used so that you may securely access the switch using the web
configurator. The SSL protocol specifies that the SSL server (the switch) must always
authenticate itself to the SSL client (the computer which requests the HTTPS connection with
the switch), whereas the SSL client only should authenticate itself when the SSL server
requires it to do so. Authenticating client certificates is optional and if selected means the SSL-
client must send the switch a certificate. You must apply for a certificate for the browser from
a CA that is a trusted CA on the switch.
Please refer to the following figure.
1 HTTPS connection requests from an SSL-aware web browser go to port 443 (by default)
on the switch’s WS (web server).