UTT Technologies Chapter 11 Firewall
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Page 182
11.2.1.3 Filtering Type of Access Rule
The Router supports three filtering types of access rule, which include IP filtering, URL
filtering and keyword filtering. All of them support access control based on schedule.
1. IP Filtering
The IP filtering rules are used to filter IP packets based on the packet header information,
such as source IP address, destination IP address, protocol type (TCP, UDP, ICMP, etc.),
TCP/UDP source port and destination port.
The filtering criteria that you can specify within an IP filtering rule include: source IP
address, destination IP address, protocol, source port, destination port, and schedule.
2. URL Filtering
The URL filtering rules are used to filter URLs based on keyword in the URL. It allows you
to filter any web page whose URL contains the specified keyword. For example, if you
want to block sex related websites, you can use the URL
keyword “sex”. This will block
any web page whose URL contains sex, such as
www.sexpicture.com
. Of course, you can
use the full URL (like
“www.yahoo.com”) to filter only the specified URL.
The filtering criteria that you can specify within a URL filtering rule include: source IP
address, filtering content (i.e., URL keyword), and schedule.
3. Keyword Filtering
The keyword filtering rules are used to block users from submitting information to the web
page based on keyword, that is, the information that contains the specified keyword (such
as pornography, gambling, etc.) cannot be submitted to any web page. The Router
supports both Chinese and English keyword filtering.
The filtering criteria that you can specify within a keyword filtering rule include: source IP
address, filtering content (i.e., keyword in the web page), and schedule.
11.2.1.4 Action of Access Rule
The action of an access rule is either
Allow
or
Deny
. As mentioned earlier, the Router
checks each received packet against the access rules in the
Access Rule List
, and the
first access rule that matches a packet determines whether the Router accepts or drops
the packet. If the rule
’s
Action
is
Allow
, the packet is forwarded. If the rule
’s
Action
is
Deny
, the packet is dropped.
Note that keyword filtering rules only support the
Deny
action.
