ELSA LANCOM Business 6000, Manual

Page: 57 / 174

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Operating modes and functions
57
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ELSA LANCOM Business 6000
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EN
number, any calls from remote stations with unknown numbers are denied
access.
You can use call numbers as a security measure with any B-channel protocol
(layers).
6.3.1 Callback
The callback function offers a special form of access privilege: This requires
the 'Callback' option to be activated in the name list for the desired caller and
the call number to be specified, if required.
The callback characteristics of your router can be controlled using the
settings in the name and number lists and the selection of the (PPP) protocol:
The router can refuse to call back.
It can call back using a preset call number.
The caller can opt to specify the call number to be used for callback.
And all the while you can use the settings to dictate how the cost of the
connection is to be apportioned. The router accepts all unit charges, except
for the unit required to send the name, if call back 'After name verification' is
set in the name list. The caller also accepts a unit if the caller is not identified
via CLIP (
C alling L ine I dentifier P rotocol). On the other hand, the caller incurs
no costs if identification of the caller's number is possible and is accepted
(callback via the D channel).
An especially effective callback method is the fast callback procedure (patent
pending). This speeds up the callback procedure considerably. The procedure
only works if it is supported by both stations. All current ELSA routers are
capable of fast callback.
6.3.2 Data packet filtering—Firewall
The firewall filters of the ELSA LANCOM Business devices offer filter
functions for individual computers and also for entire networks. These filters
effectively protect your network against intruders.
Setting up the filter
There are several options for setting up the firewall filters:
LANconfig
IP router Filtering