D-Link DES-3250TG User Manual - Ip Address Assignment

D-Link DES-3250TG Standalone Layer 2 Switch

SNMP agent. SNMP defines both the format of the MIB specifications and the protocol used to access this information over 

the network. 

The DES-3250TG supports SNMP versions 1, 2c, and 3. You can specify which version of SNMP you want to use to monitor 

and control the Switch. The three versions of SNMP vary in the level of security provided between the management station and 

the network device.   

In SNMP v.1 and v.2, user authentication is accomplished using 'community strings', which function like passwords.  The 

remote user SNMP application and the Switch SNMP must use the same community string. SNMP packets from any station 

that has not been authenticated are ignored (dropped). 

The default community strings for the Switch used for SNMP v.1 and v.2 management access are: 

public - Allows authorized management stations to retrieve MIB objects. 

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private - Allows authorized management stations to retrieve and modify MIB objects. 

SNMP v.3 uses a more sophisticated authentication process that is separated into two parts. The first part is to maintain a list of 

users and their attributes that are allowed to act as SNMP managers. The second part describes what each user on that list can 

do as an SNMP manager.  

The Switch allows groups of users to be listed and configured with a shared set of privileges. The SNMP version may also be 

set for a listed group of SNMP managers. Thus, you may create a group of SNMP managers that are allowed to view read-only 

information or receive traps using SNMP v.1 while assigning a higher level of security to another group, granting read/write 

privileges using SNMP v.3. 

Using SNMP v.3 individual users or groups of SNMP managers can be allowed to perform or be restricted from performing 

specific SNMP management functions. The functions allowed or restricted are defined using the Object Identifier (OID) 

associated with a specific MIB. An additional layer of security is available for SNMP v.3 in that SNMP messages may be 

encrypted. To read more about how to configure SNMP v.3 settings for the Switch read the section entitled Management. 

Traps 

Traps are messages that alert network personnel 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 trap recipient (or network manager). Typical traps include trap messages for Authentication Failure, Topology 

Change and Broadcast\Multicast Storm. 

MIBs 

Management and counter information are stored by the Switch in the Management Information Base (MIB). The Switch uses 

the standard MIB-II Management Information Base module. Consequently, values for MIB objects can be retrieved from any 

SNMP-based network management software. In addition to the standard MIB-II, the Switch also supports its own proprietary 

enterprise MIB as an extended Management Information Base. The proprietary MIB may also be retrieved by specifying the 

MIB Object Identifier. MIB values can be either read-only or read-write. 

IP Address Assignment 

Each Switch must be assigned its own IP Address, which is used for communication with an SNMP network manager or other 

TCP/IP application (for example BOOTP, TFTP). The Switch's default IP address is 10.90.90.90. You can change the default 

Switch IP address to meet the specification of your networking address scheme. 

The Switch is also assigned a unique MAC address by the factory. This MAC address cannot be changed, and can be found by 

entering the command "show switch" into the command line interface, as shown below.  

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