Operation Manual

06/ CONFIGURING

SECURITY SETTINGS

Additional features, including surﬁ ng restrictions and access control,

can also be conﬁ gured locally through the user interface or remotely by

a service provider.

The ﬁ rewall regulates the ﬂ ow of data between the local network and

the Internet. Both incoming and outgoing data are inspected, then

either accepted and allowed to pass through your Gateway or rejected

and barred from passing through your Gateway, according to a ﬂ exible

and conﬁ gurable set of rules. These rules are designed to prevent

unwanted intrusions from the outside, while allowing local network

users access to Internet services.

The ﬁ rewall rules specify the type of services on the Internet that are

accessible from the local network and types of services in the local

network that are accessible from the Internet.

Each request for a service that the ﬁ rewall receives is checked against

the ﬁ rewall rules to determine whether the request should be allowed

to pass through the ﬁ rewall. If the request is permitted to pass, all

subsequent data associated with this request or session is also allowed

to pass, regardless of its direction.

For example, when accessing a website on the Internet, a request

is sent to the Internet for this site. When the request reaches your

Gateway, the ﬁ rewall identiﬁ es the request type and origin, such

as HTTP and a speciﬁ c computer in the local network. Unless your

Gateway is conﬁ gured to block requests of this type from this

computer, the ﬁ rewall allows this type of request to pass to the

Internet.

When the website is returned from the web server, the ﬁ rewall

associates the website with this session and allows it to pass;