IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue - Organisation Remarks
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reasons of network security this is precisely what one does not want with a fax
server. Active ISDN cards can make up to 30 ISDN channels available. When
active ISDN cards are used, the ISDN signalling possibilities are also
available for automatic fax routing. Despite the fact that they can be used for
non-fax operations, active ISDN cards are still positively recommended for
use in fax service.
d) Fax cards (if necessary, with ISDN interface)
Special fax cards are optimised for handling the T.30 protocol. They assume
the tasks of connection setup and "negotiation" of communications
parameters. Data conversion and compression can be performed on the card,
thus considerably reducing the load on the fax server. Fax cards which offer
fax data transmission rates of at 9,600 and 14,400 bps and use of all three
compression techniques are available. These cards also have the advantage
that they generally can only handle the T.30 protocol and therefore cannot be
used either for modem operation or as a remote access component. Some fax
cards are enhanced to include an ISDN interface. The advantage of this is that
ISDN signalling can be used for fax routing.
To conclude, therefore, as a rule only active ISDN cards or fax cards should
be used on fax servers. The card must be compatible with the application
software as not every card is supported by all fax server applications. The
number of cards that are necessary depends on utilisation of the fax server.
Each channel can transmit approx. 40-50 pages of fax data per hour and per
line.
Fax server application
When selecting the applications software, both the volume of faxes which will
have to be processed over the fax server and the number of users need to be
considered.
If an E mail or workflow system already exists in the organisation, then it
should be possible to integrate the application software with these systems. It
may then be desirable for incoming and outgoing faxes to be exchanged
between the user's personal computer and the fax server using the existing
workflow or E mail system. In this connection it is also of interest whether
and how any existing address books and distribution lists can be synchronised
with the fax server's address books. Moreover, archiving of incoming and
outgoing fax transmissions should be possible in existing workflow systems.
Another factor to be considered is how fax transmissions should pass from the
user's workstation to the fax server and at what point the data should be
converted into a data format which the fax server can accept. Conversion of
the outgoing fax data at the workstation is normally effected using a printer
driver or a special fax client application. The converted data can then be
passed to the fax server either via E mail or else using the fax client
application. One option is that the user copies the converted data to a special
directory on the fax server. Finally there are fax servers for which a print
queue is configured on the network. Fax data is written to this queue by the
application software, e.g. a word processing program. It is also possible for
full data conversion to be performed on the fax server. In this case, the user
creates the file which is to be sent as a fax using appropriate application
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IT-Baseline Protection Manual: Oktober 2000
Use active ISDN cards or
fax cards
Integration into an E mail
or workflow system
Transmission from
workstation to fax server