IT Baseline Protection Manual - The Information Warfare Site

Safeguard Catalogue - Organisation Remarks
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Access to the mailbox should be protected by a PIN. Even when the mailboxes
not used, the preconfigured PIN should be changed early on to prevent use by
third parties.
Messages recorded should be listened to at regular intervals. All the users
must be informed as to how the answerphone function works.
Call diversion
The call diversion function enables incoming calls to be diverted to the
mailbox or to a different call number. There are several variants of this:
- All incoming calls are diverted.
- Calls are only diverted when the line is busy.
- Calls are only diverted if a connection cannot be established to the phone,
e.g. due to a gap in coverage or because the mobile phone has been
switched off.
- Certain types of call can be diverted, e.g. voice, data or fax calls.
However, it should be noted here that call diversions to landline network
connections can incur high charges as the person who is being called has to
pay the diversion costs himself.
Call restrictions
Call restrictions can be used to block calls to or from a call number. These
functions are provided via the network provider and can be modified on the
mobile phone. Normally it is necessary to enter a password.
Call restrictions can be a good idea if the mobile phone is to be passed on to
third parties. There are various types of call restrictions:
- Barring of all outgoing calls
This means that only incoming calls can be handled, and apart from
emergency numbers it is not possible to initiate any outgoing calls.
- Barring of all outgoing international calls
This restriction means that only numbers in the country in which the user is
currently located may be dialled. Calls from abroad can continue to be
received.
- Barring of all outgoing international calls except for calls to the user's
home country.
This allows calls to be made back to the home country (i.e. the country of
the network provider). Calls to other countries are barred.
- Barring of all incoming calls
It is only possible to make outgoing calls. This ensures that there are no
interruptions from incoming calls.
- Barring of all incoming calls when the user is abroad
Within the home country calls can continue to be made as normal.
However, when the user is abroad, no telephone calls can be received any
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IT-Baseline Protection Manual: Oktober 2000