Netopia D3100-I, Руководство пользователя

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Monitoring Tools 7-59
By default, the read-only and read/write community strings are set to “public” and “private,” respectively. You
should change both of the default community strings to values known only to you and trusted system adminis-
trators.
To change a community string, select it and enter a new value.
Setting the Read-Only and Read-Write community strings to the empty string will block all SNMP requests to the
Netopia D-Series. (The Netopia D-Series may still send SNMP Traps if those are properly enabled.)
This allows the administrator to block SNMP access to the Netopia D-Series, and to provide more granular
control over the allowed SNMP operations to the Netopia D-Series.
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Setting only the Read-Write community string to the empty string will block SNMP Set Requests to the
Netopia D-Series, but Get Requests and Get-Next Requests will still be honored using the Read-Only
community string (assuming that is not the empty string).
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Setting only the Read-Only community string to the empty string will not block Get Requests or Get-Next
Requests since those operations (and Set Requests) are still allowed using the (non-empty) Read-Write
community string.
Even if you decide not to use SNMP, you should change the community strings. This prevents unauthorized
access to the Netopia D-Series through SNMP. For more information on security issues, see
“Security” on
page 8-61 .
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An SNMP trap is an informational message sent from an SNMP agent (in this case, the Netopia D-Series) to a
manager. When a manager receives a trap, it may log the trap as well as generate an aler t message of its own.
Standard traps generated by the Netopia D-Series include the following:
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An authentication failure trap is generated when the Netopia D-Series detects an incorrect community
string in a received SNMP packet.
Authentication Traps Enable must be On for this trap to be generated.
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A cold star t trap is generated after the Netopia D-Series is reset.
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An inter face down trap (ifDown) is generated when one of the Netopia D-Series’s inter faces, such as a
por t, stops functioning or is disabled.
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An inter face up trap (ifUp) is generated when one of the Netopia D-Series’s inter faces, such as a por t,
begins functioning.
The Netopia D-Series sends traps using UDP (for IP networks).
You can specify which SNMP managers are sent the IP traps generated by the Netopia D-Series. Up to eight
receivers can be set. You can also review and remove IP traps.
To go to the IP Trap Receivers screen, select IP Trap Receivers . The IP Trap Receivers screen appears.