vRouter NCP does not include the clear or purge commands, nor do the set
commands have an all argument. The permanent database is always copied to
the volatile database when the router starts, restarts, or boots.
vA router NCP command can have only one argument.
vNCP does not have the concept of lines. Tosee the data that a DECnet-VAX
NCP show line command displays, use the GWCON interface and network
commands.
vRouter NCP does not support cross-network commands:
– Router NCP does not include the tell command, which requests NCP
commands on other nodes.
– Similarly, router NCPdoes not support protocol requests from other DNA
routers to execute NCP commands at the router on their behalf.
Important
Before configuring DNA IV,you need to be aware of the optional security
features discussed in:
v“Managing TrafficUsing Access Control”
– Provides additional security by limiting access within routers in the
network.
v“Managing TrafficUsing Area Routing Filters” on page 256
– Limits access to group of areas from other areas
– Allows blending of two DECnet address spaces
If you already are familiar with these topics, skip these two sections and begin
reading at “Configuring DNA IV”on page 261.
Managing Traffic Using Access Control
Access control protects one group of nodes from other nodes on the network.
Routers make all nodes on a network accessible to each other. Usually,the main
forms of security are passwords and conservative use of DNA IV proxy access at
the host level.
However, due to differences in the security level of machines, you might need to
provide additional security by limiting access within the routers in the network. The
DNA forwarder enables you to do this using access controls.
Generally, access controls are not recommended due to the following liabilities:
vAccess controls affect performance of the router because every packet is tested.
The more complicated the access control configuration, the greater the
performance impact.
vAccess controls are difficult to configure and errors in configuration are difficult to
diagnose.
vAccess controls cannot hide a node from the routing protocols. The node
remains visible from all routers in its area.
Note: Access controls do not guarantee security; they only make intrusion more
difficult. The DNAIV routing protocols used on Ethernet and other
broadcast media do not have built-in security features.
Using DNA IV
Chapter7. Using DNA IV 253