User's Manual

How Firewall Rule Enforcement Works
X Family LSM User’s Guide V 2.5.1 65
STEP 1 The user starts a web browser. The web browser resolves the DNS name for the URL and
initiate a TCP connection to the target web server via the X family device.
STEP 2 The X family device inspects the session header and identifies the following information
about the request:
• Source IP — The address of the device that initiated the request.
• Destination IP — The address of the device for which the request is intended.
• Application — Type of service/content and authenticated user (if any).
STEP A Using its routing table, the device decides which Security Zone the session has come
from and which zone it is going to.
STEP 3 The device searches for the first firewall rule in its list that matches the session request. Rules
are evaluated based on what options are configured:
•user authentication
• IP protocol service
• schedule
•source zone
• destination zone
• web filtering