Hughes HX200, Руководство по установке

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Chapter 5 • The System Control Center
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1038054-0001 Revision B
Understanding how the
firewall works
The Firewall Configuration page provides controls for creating
and managing firewall rules. The firewall feature provides
firewall protection for the computers connected to the HX200.
The firewall rules that you create apply only to inbound traffic;
that is, network traffic sent from the HX system gateway to the
satellite router.
Think of firewall rules as templates against which network
packets received from the system gateway are compared. When a
packet matches the value or values defined in a rule, the
rule
action is applied to the packet. For example, if you:
•
create a firewall rule that matches all traffic targeted to port
22 (that is, traffic from any source IP address to any
destination IP address with a destination port of 22), and
•
define the rule action as BLOCKED,
then packets with a destination port number of 22 addressed to
any IP device behind the satellite router will be dropped.
Traffic is matched against firewall rules in the order that the rules
are listed in the firewall rule table. The action of the first
matching firewall rule is applied; no further matching is
attempted after the first successful match.
Firewall rule restrictions
The following restrictions apply to firewall rules:
•
The number of rules is limited to 20
•
The number of ports defined in the Source Port and
Destination Port fields is limited to 5 individually
enumerated ports. Entering a port range is not supported.
•
Rules are applied in the order listed in the firewall rule list.
The rules cannot be reordered without deleting and recreating
them.
•
If ICMP is selected as the Protocol Type, all ICMP packets
(ICMP Type 255) are filtered.
If the Protocol Type is set to either TCP or UDP, a minimum of
one port number must be defined in either the
Source
or
Destination Port Number
fields.
Creating firewall rules
To create firewall rules:
1. Click the Firewall Configuration link in the System Control
Center navigation area.
The Firewall Configuration page appears.
2. Click Add Rule .