In this chapter, you would find a description of toll fraud—a potential security issue in any organization. You can also find information that may help you to develop preventive measures, and best practices to avoid toll fraud.
Using Restriction Tables to Help Prevent Toll Fraud
Toll fraud is defined as any toll (long distance)
call that is made at the expense of your organization and in violation of its
policies. Cisco Unity Connection provides restriction tables that you can use
to help guard against toll fraud. Restriction tables control the phone numbers
that can be used for transferring calls, for message notification, and for
other Unity Connection functions. Each class of service has several restriction
tables associated with it, and you can add more as needed. By default,
restriction tables are configured for basic toll fraud restrictions for a dial
plan with a trunk access code of 9. Restriction tables should be adjusted for
your specific dial plan and international dialing prefixes.
To prevent toll fraud by users, administrators,
and even outside callers who have improperly gained access to a Cisco Unity
Connection mailbox, implement the following changes:
Set up all restriction tables to block calls
to the international operator. When this is done, a person cannot dial out to
or configure call transfers from an extension to the international operator
(for example, a trunk access code of 9 followed by 00 to dial the international
operator) for placing international calls.
If Unity Connection is integrated with two
phone systems, add restriction table patterns to match applicable trunk access
codes for both phone system integrations. For example, if the trunk access code
for one of the phone system integrations is 99 and you want to restrict the
call pattern 900, you would also restrict the pattern 99900. When patterns that
include the trunk access codes are restricted, attempts to bypass the
restriction table by first accessing either trunk and then dialing the
international operator is blocked.
For those in your organization who do not need
to access international numbers to do their work, set up restriction tables to
block all calls to international numbers. This prevents a person who has access
to a Unity Connection mailbox that is associated with the restriction table
from configuring call transfers or fax delivery from that extension to an
Set up restriction tables to permit calls only
to specific domestic long distance area codes or to prohibit calls to long
distance area codes. This prevents a person who has access to a Unity
Connection mailbox that is associated with the restriction table from
configuring call transfers or fax delivery from that extension to a long
Restrict the numbers that can be used for
system transfers—a feature that allows callers to dial a number and then
transfer to another number that they specify. For example, set up the
applicable restriction tables to allow callers to transfer to a lobby or
conference room phone, but not to the international operator or to a long
distance phone number.
Restricting Collect Calling Options
We recommend that you work with your
telecommunications provider to restrict the collect calling option on your
incoming phone lines, if appropriate.