SonicWALL TZ 190 Manuale Utente

Pagina di 843
Firewall > SSL Control
496
SonicOS Enhanced 4.0 Administrator Guide
Key Concepts to SSL Control
  •
SSL- Secure Sockets Layer (SSL) is a network security mechanism introduced by 
Netscape in 1995. SSL was designed “to provide privacy between two communicating 
applications (a client and a server) and also to authenticate the server, and optionally the 
client.” SSL’s most popular application is HTTPS, designated by a URL beginning with 
https:// rather than simply http://, and it is recognized as the standard method of encrypting 
web traffic on the Internet. An SSL HTTP transfer typically uses TCP port 443, whereas a 
regular HTTP transfer uses TCP port 80. Although HTTPS is what SSL is best known for, 
SSL version, Cipher 
Strength, and Certificate 
Validity Control
SSL Control provides additional management of SSL sessions 
based on characteristics of the negotiation, including the ability to 
disallow the potentially exploitable SSLv2, the ability to disallow 
weak encryption (ciphers less than 64 bits), and the ability to 
disallow SSL negotiations where a certificate’s date ranges are 
invalid. This enables the administrator to create a rigidly secure 
environment for network users, eliminating exposure to risk 
through unseen cryptographic weaknesses, or through disregard 
for or misunderstanding of security warnings. 
Zone-Based Application
SSL Control is applied at the zone level, allowing the administrator 
to enforce SSL policy on the network. When SSL Control is 
enabled on the zone, the SonicWALL looks for Client Hellos sent 
from clients on that zone through the SonicWALL will trigger 
inspection. The SonicWALL then looks for the Server Hello and 
Certificate that is sent in response for evaluation against the 
configured policy. Enabling SSL Control on the LAN Zone, for 
example, will inspect all SSL traffic initiated by clients on the LAN 
to any destination zone.
Configurable Actions 
and Event Notifications
When SSL Control detects a policy violation, it can log the event 
and block the connection, or it can simply log the event while 
allowing the connection to proceed.
Feature
Benefit