iPECS SBG-1000 User Manual

iPECS SBG-1000 User Manual (DATA Features)
intrusions from the outside, while allowing home users access to the Internet services that they
require.
The firewall rules specify what types of services available on the Internet may be accessed from
the home network and what types of services available in the home network may be accessed
from the Internet. Each request for a service that the firewall receives, whether originating from the
Internet or from a computer in the home network, is checked against the set of firewall rules to
determine whether the request should be allowed to pass through the firewall. If the request is
permitted to pass, then all subsequent data associated with this request (a “session”) will also be
allowed to pass, regardless of its direction.
For example, when you point your browser to a Web page, a request is sent to the Internet for
retrieving and loading this page. When this request reaches iPECS SBG-1000, its firewall identifies
the request’s type and origin. In the Web browsing example, HTTP is the request’s type, and your
PC is its origin. Unless you have configured iPECS SBG-1000’s Access Control feature to block
requests of this type originating from your PC, the firewall will allow this request to pass out onto
the Internet (for more on configuring iPECS SBG-1000’s Access Control, refer to Section 5.2.2).
When the Web page is returned from the Web server, the firewall associates it with the current
connection and allows it to pass, regardless of whether HTTP access from the Internet to your
home network is blocked or permitted. It is the origin of the request, not the subsequent responses
to this request, that determines whether a connection can be established or not.
5.2.2 Controlling Your Network’s Access to Internet Services
You may want to block specific computers within the home network (or even the whole network)
from accessing certain services available on the Internet. For example, you may want to prohibit
one computer from browsing the Web, another computer from transferring files using FTP, and the
whole network from accessing email (by blocking the outgoing requests to POP3 servers on the
Internet). The ‘Access Control’ screen enables you to apply restrictions on the types of connection
requests that may pass from the home network out to the Internet, and to block the corresponding
network traffic in both directions. In addition, this screen can be used for allowing access to
specific services when the ‘Maximum’ security is applied (as described in Section 5.2.1).
To block access to a service available on the Internet:
1. Click the ‘Access Control’ link under the ‘Firewall’ menu item. The ‘Access Control’ screen
appears.
Figure 5.4 Access Control
2. Click the ‘New Entry’ link. The ‘Add Access Control Rule’ screen appears.
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