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VoIP/(802.11g) ADSL2+ (VPN) Firewall Router
Chapter 4: Configuration
60
When using Virtual Servers your PCs will be exposed to the degree
specified in your Virtual Server settings provided the ports specified are
opened in your firewall packet filter settings.
Firewall and Access Control
Your router includes a full SPI (Stateful Packet Inspection) firewall for controlling Internet access from
your LAN, as well as helping to prevent attacks from hackers. In addition to this, when using NAT, the
router acts as a “natural” Internet firewall, as all PCs on your LAN will use private IP addresses that
cannot be directly accessed from the Internet.
Firewall
: Prevents access from outside your network. The router provides three levels of security
support:
NAT natural firewall
: This masks LAN users’ IP addresses which is invisible to outside users on the
Internet, making it much more difficult for a hacker to target a machine on your network. This natural
firewall is on when NAT function is enabled.
Firewall Security and Policy (General Settings)
: Inbound direction of Packet Filter rules to prevent
unauthorized computers or applications accessing your local network from the Internet.
Intrusion Detection
: Enable Intrusion Detection to detect, prevent and log malicious attacks.
Access Control
: Prevents access from PCs on your local network:
Firewall Security and Policy (General Settings)
: Outbound direction of Packet Filter rules to prevent
unauthorized computers or applications accessing the Internet.
URL Filter
: To block PCs on your local network from unwanted websites.
Here are the items within the
Firewall
section:
General Settings, Packet Filter, Intrusion Detection,
URL Filter, IM/P2P Blocking
and
Firewall Log.
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General Settings
You can choose not to enable Firewall and still able to access to URL Filter and IM/P2P Blocking or
enable the Firewall using preset filter rules and modify the port filter rules as required. The Packet Filter is
used to filter packets based-on Applications (Port) or IP addresses.
There are four options when you enable the Firewall, they are:
~
All blocked/User-defined
: no pre-defined port or address filter rules by default, meaning that
all inbound (Internet to LAN) and outbound (LAN to Internet) packets will be blocked. Users have to
add their own filter rules for further access to the Internet.
~
High/Medium/Low security level:
the predefined port filter rules for High, Medium and Low
security are displayed in Port Filters of Packet Filter.
Select either
High, Medium
or
Low
security level
to enable the Firewall. The only difference between
these three security levels is the preset port filter rules in the Packet Filter. Firewall functionality is the
same for all levels; it is only the list of preset port filters that changes between each setting. For more
detailed on level of preset port filter information, refer to
Table 1: Predefined Port Filter
.
If you choose of the preset security levels and add custom filters, this level of filter rules will be saved
even and do not need to re-configure the rules again if you disable or switch to other firewall level.
The “
Block WAN Request
” is a stand-alone function and not relate to whether security enable or disable.
Mostly it is for preventing any scan tools from WAN site by hacker.
Any remote user who is attempting to perform this action may result in
blocking all the accesses to configure and manage of the device from the
Internet.
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Packet Filter
This function is only available when the Firewall is enabled and one of these four security levels is chosen
(All blocked, High, Medium and Low).
The preset port filter rules in the Packet Filter must modify
accordingly to the level of Firewall, which is selected.
See
Table1: Predefined Port Filter
for more
detail information.
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Example:
Predefined Port Filters Rules
The predefined port filter rules for High, Medium and Low security levels are listed. See Table 1.
Note:
Firewall – All Blocked/User-defined, you must define and create the port filter rules yourself.
No
predefined rule is being preconfigured.
Table 1: Predefined Port Filter
Port Number
Firewall - Medium
Protocol
Inbound
Outbound
TCP(6)
NO
YES
UDP(17)
NO
YES
TCP(6)
NO
YES
TCP(6)
NO
YES
TCP(6)
NO
YES
TCP(6)
NO
YES
TCP(6)
NO
YES
NEWS(NNTP)
TCP(6)
NO
YES
UDP(17)
YES
YES
ICMP(1)
NO
YES
TCP(6)
NO
YES
TCP(6)
NO
YES
TCP(6)
NO
YES
UDP(17)
NO
YES
TCP(6)
NO
NO
TCP(6)
NO
YES
TCP(6)
N/A
N/A
TCP(6)
N/A
N/A
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VoIP/(802.11g) ADSL2+ (VPN) Firewall Router
Chapter 4: Configuration
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UDP(17)
N/A
N/A
VEDIO
TCP(6)
N/A
N/A
Inbound:
Internet to LAN ;
Outbound:
LAN to Internet.
YES:
Allowed ;
NO:
Blocked ;
N/A:
Not Applicable

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