Technical data

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• “Allow” mode will only pass the packets that match the “allow” filters in the filter database and discard all
others.
Up to 40 “allow” filters or 40 “deny” filters can be activated from the filter database.
You enter the filters, including the pattern, offset, and filter mode, into a filter database. If you intend to restrict
specific stations or subnetworks from bridging, then add the filters with a “deny’ designation. Then enable
filtering for deny. If you wish to allow only specific stations or subnetworks to bridge, then add the filters with an
“allow” designation and enable filtering for “allow”. Add each filter with the following command:
filter br add
[
pos
][
data
]deny|allow
where [
pos
] is the byte offset within a packet (number from 0-127) to a [
data
] (a hex number up to 6 bytes). This
data and offset number can be used to identify an address, protocol id or data content. After you have entered all
of the filters, verify your entries with the following command:
filter br list
If you have entered an incorrect filter, delete the filter using the
filter br del
command. When you are satisfied
with the filter list, save the filtering database with the
save filter
command. You must reboot the router to load the
filtering database. Then enable bridging filtering with the following command:
filter br use
none|deny|allow
Test the filtering configuration by accessing a remote destination identified in the filter.
Enable/Disable Internet Firewall Filtering
The router supports IP Internet Firewall Filtering to prevent unauthorized access to your system and network
resources from the Internet. This filter discards packets received from the WAN which have a source IP address
recognized as a local LAN address. You can set Internet Firewall Filtering using the command:
eth ip firewall
on|off|list
The Internet Firewall defaults to ON during initial configuration and is active
only
when Ethernet LAN IP routing
is on.
As described earlier, Ethernet LAN IP routing is controlled by the commands:
eth ip enable
eth ip disable
Therefore, at initial configuration, you need only enable IP routing to activate the Internet Firewall Filter. If you
do not wish the router to perform IP Internet Firewall Filtering while IP routing, you must turn OFF the Firewall
Filter. Remember to save and reboot
if you alter IP routing status.