Ring security configuration, About ring security, Chapter 6 – Cabletron Systems SPECTRUM TRMMIM User Manual
Page 103: About ring security -1

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Chapter 6
Ring Security Configuration
Selecting a ring for which to set security; configuring the Allowed and Disallowed Station Lists; 
selecting ring security levels
About Ring Security
The Ring Security application allows you to control access to the Token Ring 
networks being managed by the TRMMIM by specifying an “Allowed List” of 
stations permitted to enter the ring, a “Disallowed List” of stations removed from 
the Allowed List, and a security mode which controls the ring’s response to 
stations illegally attempting to enter the ring. 
The Allowed List, which by default contains the MAC address of each station 
known or permitted on the ring network when security is enabled, is a database 
stored at the TRMMIM itself. Each Token Ring hub can store up to 250 station 
MAC addresses in the Allowed List, which is maintained in its battery-backed 
Non-Volatile Random Access Memory (NVRAM). When you power up or reset 
the TRMMIM, all MAC addresses will be retained and ring security resumes its 
previous state.
You first build the Allowed List either by enabling ring security with the “Warn” 
security mode activated (as described in 
) —
which will add the MAC addresses of all stations currently detected on the ring to 
the Allowed List — or by individually entering the MAC addresses of each station 
using the Add button. Once the list has been built and updated, you can switch 
the security mode to “Warn and Remove,” which will issue a trap to your 
management station and send a Remove MAC frame to any unauthorized station 
(that is, one not in the Allowed List) which tries to enter the ring. You can add to 
the allowed list at any time.
The Disallowed List acts as a repository for the MAC addresses of stations that 
have been removed from the Allowed List, or station addresses that you 
administratively enter. These addresses are stored in a “Disallowed” database 
that is maintained at your management workstation. The number of entries in the 
database is limited only by disk space. You can add to the Disallowed List either 
