D-Link DES-3326 - Manual (Page 26)

DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
In addition, you can also set an IP Address for a gateway router. This becomes necessary when the
network management station is located on a different IP network from the Switch, making it necessary
for management packets to go through a router to reach the network manager, and vice-versa.
For security, you can set in the Switch a list of IP Addresses of the network managers that you allow to
manage the Switch. You can also change the default SNMP Community Strings in the Switch and set
the access rights of these Community Strings. In addition, a VLAN may be designated as a
Management VLAN.
Traps
Traps are messages that alert you of events that occur on the Switch. The events can be as serious as a
reboot (someone accidentally turned OFF the Switch), or less serious like a port status change. The
Switch generates traps and sends them to the network manager (trap recipient).
Trap recipients are special users of the network who are given certain rights and access in overseeing
the maintenance of the network. Trap recipients will receive traps sent from the Switch; they must
immediately take certain actions to avoid future failure or breakdown of the network.
You can also specify which network managers may receive traps from the Switch by entering a list of
the IP addresses of authorized network managers. Up to four trap recipient IP addresses, and four
corresponding SNMP community strings can be entered.
SNMP community strings function like passwords in that the community string entered for a given IP
address must be used in the management station software, or a trap will be sent.
The following are trap types the switch can send to a trap recipient:
• Cold Start This trap signifies that the Switch has been powered up and initialized such that
software settings are reconfigured and hardware systems are rebooted. A cold start is
different from a factory reset in that configuration settings saved to non-volatile RAM used to
reconfigure the switch.
• Warm Start This trap signifies that the Switch has been rebooted, however the POST (Power
On Self-Test) is skipped.
• Authentication Failure This trap signifies that someone has tried to logon to the switch
using an invalid SNMP community string. The switch automatically stores the source IP
address of the unauthorized user.
• New Root This trap indicates that the Switch has become the new root of the Spanning Tree,
the trap is sent by the switch soon after its election as the new root. This implies that upon
expiration of the Topology Change Timer the new root trap is sent out immediately after the
Switch’s election as the new root.
• Topology Change (STP) A Topology Change trap is sent by the Switch when any of its
configured ports transitions from the Learning state to the Forwarding state, or from the
Forwarding state to the Blocking state. The trap is not sent if a new root trap is sent for the
same transition.
• Link Up This trap is sent whenever the link of a port changes from link down to link up.
• Link Down This trap is sent whenever the link of a port changes from link up to link down.
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