S 4.37 Blocking fax sender numbers

Initiation responsibility: IT Security Management

Implementation responsibility: Fax Officer

So that certain fax transmissions can be prevented from obstructing the personal fax machine, e.g. overloading by fax advertising campaigns, it is possible to block the corresponding fax sender numbers.

Some modern fax machines (group 4) are able to evaluate sender numbers and thus prevent the reception of fax messages from certain selected ones.

Another alternative is the installation of a closed user group by the telephone utility (with charges) if the sender and recipient are connected to digital exchanges. This alternative is offered by some modern PBX facilities (cf. Chapter 8.1 Telecommunications System (Private Branch Exchange).

Additional controls:

• Is there a requirement for blocking certain sender numbers?

• Are the fax officers aware of the above-mentioned types of safeguards?