User`s guide

DSL-500 ADSL Router User’s Guide
57
Advanced Filtering and Firewall (Screen #3)
In the third Advanced Filtering window you will define the rule applied for the
chosen subset. Again you can supply a name for the subset in the
Comment
field
and click the box on the right to
enable the Filter Rule
.
In the
Pass or Block
field select the action to be performed on the IP packets,
the default is
Pass Immediately
. All blocked packets will be dropped.
In the
Direction
field choose either
In
or
Out
from the pull down menu. You can
block IP packets from coming into the network, by selecting
In
, blocking packets
from a specific IP address for example. Or you can block packets from a specific
IP address or subnet from leaving the LAN by selecting
Out
, for example, to block
Internet access for a specific host.
The
Protocol
field allows you to block packets based on the protocol used. You
may choose to block ICMP, TCP or UDP transmissions from the pull-down menu.
You must next specify the
Source
and
Destination IP Addresses
as well as
their
Subnet Mask
. This will block the packets from or destined to any specified
IP address from passing through the Router.
Finally you can specify individual protocol ports or an entire range of protocol
ports to be blocked for the
Source
or
Destination
. Type the
Start Port
number