Symantec Security 5600 Series, Security 5400 Series,Clientless VPN 4400 Series, Руководство администратора

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Chapter
8
Controlling traffic at the security
gateway
This chapter includes the following topics:
■
How the security gateway controls traffic
■
Creating rules and filters to control traffic through the firewall
■
Understanding and using rules
■
Controlling traffic by date and time
■
Using packet filters to allow or deny traffic
■
Blocking inappropriate content with content filtering
How the security gateway controls traffic
When you first set up the security gateway, if you do not create HTTP, FTP and mail rules through the
System Setup Wizard, by default, the security gateway blocks all traffic.
Your corporate security plan identifies the kinds of access you want to provide. If you do not have a
security plan, see
Symantec Gateway Security 5000 Series v3.0 Installation Guide .
The security gateway includes the following features that let you allow or deny traffic.
Rules Rules let you define the most granular access through the security gateway.
To create a basic rule, you specify where the traffic is coming from and where it is going, the
interfaces through which it enters and leaves the security gateway, the protocols that are in
effect, and whether the traffic is allowed or denied.
In addition, with rules, you can specify access times, authentication, alert thresholds for
logging, additional antivirus and antispam protections, and content filtering restrictions.
Packet Filters Packet filters specify an allow or a deny action with regards to a protocol, traffic direction,
and pair of network entities.
You apply packet filters to interfaces and tunnels to restrict the types of packets that are
passing into or out of the security gateway.
Packet filters are both simple and powerful. By learning how to use them, you can reduce a
significant portion of undesired traffic.
A well-constructed packet filter reduces a significant portion of undesired traffic, freeing
up valuable resources to address legitimate connections.
Content filtering Content filtering lets you control Web access through the security gateway by defining
URLs, MIME types, and newsgroups to which you allow or deny user access.
Content filtering is not used on its own. Once configured, it is applied to rules to further
control traffic through the security gateway.