Facility Restriction Levels And Remote Access - Lucent Technologies MERLIN LEGEND Release 6.0 Network Reference Manual

MERLIN LEGEND Communications System Release 6.0
Network Reference 555-660-150
4 Security

Facility Restriction Levels and Remote Access

!
SECURITYlALERT:
Networked systems require special attention to security issues. Follow the
rules below when setting up and planning your system for network use.
Facility Restriction Levels and
Remote Access
Facility Restrictions Levels (FRLs) are number values from 0 to 6 that are used to
allow or disallow calling. FRLs apply to the following four aspects of systems in a
network:
Automatic Route Selection Routes. ARS routes are assigned to
subpatterns that the system selects according to the time of day. Each
route is assigned an FRL. An FRL of 6 is the most restrictive, and an FRL
of 0 is the least restrictive. Factory-set ARS route FRLs are as follows:
— Routes assigned to Default Toll Tables: 3
— Routes assigned to the Default Local Table: 2
Uniform Dial Plan Routes. UDP routes are associated with patterns that
also specify digit manipulation for directing calls to non-local extensions
over tandem facilities, or directing non-local extension calls to PSTN
facilities. Like ARS routes, UDP routes are assigned FRLs. The factory
setting for UDP routes is 3.
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
Default Class-of-Restriction Settings" on page 4–6
Extension and ARS FRLs should be carefully and stringently
assigned in order to prevent unauthorized trunk-to-trunk transfers to
local PSTN facilities.
this feature in a networked system.
Table 4–1, page 4–3
4
Issue 1
February 1998
Page 4-5
"Remote Access
for details.
explains the operation of