3Com LINKBUILDER 3C18500, Руководство пользователя

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DUA1850-0AAA0 5
CAUTION: If you are installing the system for the first time and, if you
intend to use the remaining ports on a module with the link set to
‘disable on power-up’, you will need to enable them individually via the
Network Manager.
S ecurity may be set up at the same time as Resilience, but only using a
network manager.
Port Security
Network security is a prime concern today. There is a need to detect
and block any attempt by an unauthorized party to access your
network, and copy and manipulate your data. Using a Transcend
Network Manager, you may set ports to be secure at critical points in
your network. In this way you create a series of ‘security gates’ to
prevent the invader from accessing the rest of the network.
LAN Security Architecture (LSA) is controlled overall by the
management module, but detail is available only to SNMP
management applications such as the Transcend range. LSA allows only
frames intended for a specified station to be received by that station.
All other stations receive corrupted frames. This is in addition to the
password protection and different access levels which are built into the
management system.
One security element is the provision of ‘Need to Know’ (NTK) filtering.
A repeater examines each frame to check the destination address
against its authorized station database for that port. Any unauthorized
station attached to its ports will receive the frame, but in a deliberately
corrupted form. Only authorized stations will receive the true frame.
You have the option of examining incoming frames. If you enable this
function from your management application, these are checked for
source address. If the source address is not found in the authorized
table, the source port will be disabled (Disconnect Unauthorized Device
— DUD) and a trap will be sent to the network manager.
NTK and DUD are available on secure repeater modules.