5.5.5. Implementing IP Security
The CMS can be configured to restrict unauthorized IP addresses
from establishing an inbound telnet connection to the unit. This
allows the user to grant Telnet access to only a specific group of
IP addresses, or block a particular IP address. In the default
state, the CMS accepts incoming IP connections from all hosts.
To configure the IP Security feature, proceed as follows:
1. Access the Network Parameters menu as described in
Section 5.5.4. Note that the Network Parameters menu is
only available in Supervisor Mode.
2. When the Network Parameters menu appears, type 4and
press [Enter] to access the IP Security menu (Figure 5.4).
3. The IP Security Menu lists five IP Security “masks” along
with the selected permit/deny action for each mask.
a) Each Security Mask prompt defines a specific IP
address or range of IP addresses. Each Mask Action
prompt selects the permit/deny action for the
b) Masks are listed in order of ascending priority; Mask 1
has the lowest priority, and Mask 5 has the highest.
c) Masks have a cumulative effect; high priority masks
supersede the effect of lower priority masks.
d) Each IP Address consists of a series of four eight bit
numbers. The number 255 is used as a wild card.
Figure 5.4: IP Security Menu