User's Manual

752 CHAPTER 17: USING 3COM NETWORK DIRECTOR ON A MULTI-SITE NETWORK
■ The WAN router may have an access control list (ACL) configured that
prevents management from the device from any unauthorized
devices. If the PC that 3Com Network Director is running on is not
listed in the ACL then 3Com Network Director will be unable to fully
discover the router. Please refer to the user guide of your WAN router
for details of whether it supports ACL security and how to configure it
if it does.
■ SNMP management of the WAN router may have been disabled,
either across the entire router, or on specific interfaces or IP addresses
of the router. SNMP can be used to configure devices and so it is
common for WAN routers to have SNMP management disabled, at
least on their WAN interfaces, to prevent malicious changes to the
configuration.
■ If SNMP management of the WAN router has been disabled across the
entire router then 3Com Network Director will be unable to fully
discover the router. In order for 3Com Network Director to be able to
fully discover the router you will need to enable SNMP management
on at least one interface on your network.
■ If, on the other hand, SNMP management has only been disabled on
certain interfaces or IP addresses then you may still be able to fully
discover the router by running the Network Discovery against a
different subnet that the router has an IP address on.
Extending the available access to a WAN router by adding more devices
into an ACL or enabling SNMP management on additional interfaces can
open your network to malicious attacks if not correctly configured.