AudioCodes MP-26 series, Руководство пользователя

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User's Manual 254 Document #: LTRT-23510
MP-26x/MP-27x Multimedia Home Gateway
14.1 General Security Level Settings
Use the 'Security Settings' screen to configure the device's basic security settings.
Figure 14-2: General Security Level Settings
The firewall regulates the flow of data between the home network and the Internet. Both
incoming and outgoing data are inspected and then either accepted (allowed to pass
through the device) or rejected (barred from passing through the device) according to a
flexible and configurable set of rules. These rules are designed to prevent unwanted
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 in 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") are also allowed to pass, regardless of its direction.
For example, when you point your Web browser to a Web page on the Internet, a request
is sent out to the Internet for this page. When the request reaches the device, the firewall
identifies the request type and origin--HTTP and a specific PC in your home network, in
this case. Unless you have configured access control to block requests of this type from
this computer, the firewall allows this request to pass out onto the Internet (see 'WAN
PPPoE' on page
212 for more on setting access controls). When the Web page is returned
from the Web server the firewall associates it with this session and allows it to pass,
regardless of whether HTTP access from the Internet to the home network is blocked or
permitted.
Note that it is the origin of the request , not subsequent responses to this request, that
determines whether a session can be established or not.