Lucent Technologies MERLIN LEGEND Release 6.1 Feature Reference page 728

MERLIN LEGEND Communications System Release 6.1
Feature Reference 555-661-110
Features
Tandem Switching
!
SECURITYlALERT:
Networked systems require special attention to security issues. Follow the
rules below when setting up and planning your system for network use.
To implement this operation where ARS calls are routed to or via your system,
consult System Programming , and
the section about remote access. The following general steps outline the
procedures:
Do not assign the private trunks for remote networked users to remote
access.
Set the options listed below for the remote access default COR on your
system. If your system is linked to the private network by tandem tie
facilities (analog,T1-emulated voice and/or data), assign the settings to all
tie trunks. If only tandem PRI trunks link your system to the private
network, assign the settings to all non-tie trunks. If both tandem tie and
tandem PRI trunks link your system to the private network, assign the
remote access default CORs to their respective types of trunks.
— In a network, this setting should be turned on in order to require barrier
Ensure that barrier codes are required for incoming remote access
calls received on PSTN PRI dial-plan routed and DID facilities, as
well as those calls that are made from the local system by dialing
the Remote Access code (889, for example). When you program the
default COR, turn the barrier code requirement on. This setting is
ignored for ARS calls and calls to non-local extensions across the
network. However, it is still applied to DID and PRI dial-plan routed
remote access calls as well as to calls received on a tandem trunk
and routed to a Remote Access code. Because the COR Calling
Restriction must be set to unrestricted for network calling, using
barrier codes on these facilities is essential in order to apply security
measures. When a Remote Access code is included in the non-local
dial plan of the calling system, the caller's barrier code FRL on the
called system is compared to the UDP or ARS route FRL on the
called system. See the Feature Reference and "Remote Access
Default Class-of-Restriction Settings" for details.
Extension and ARS FRLs should be carefully and stringently
assigned in order to prevent unauthorized trunk-to-trunk transfers to
local PSTN facilities.
code entry on calls that arrive from the PSTN over DID or PRI dial-plan
routed facilities or that are made by dialing a Remote Access code
included in the non-local dial plan. When barrier codes are not required,
the remaining default COR settings apply to PSTN calls as well as
network calls. This poses a security risk and does not allow adequate
protection against toll fraud. The barrier code requirement is ignored for
calls on tandem trunks, but the remaining default COR setting does
apply to such calls.
"Class of Restrictions (COR)" on page 586
Issue 1
August 1998
Page 679
in