Important Points to Remember• Typically, 5-second timeout and 3-second retry values on an SNMP server are sufficient for both LAN and WAN applications. If youexperience a timeout with these values, increase the timeout value to greater than 3 seconds, and increase the retry value to greaterthan 2 seconds on your SNMP server.• User ACLs override group ACLs.Set up SNMPAs previously stated, Dell Networking OS supports SNMP version 1 and version 2 that are community-based security models.The primary difference between the two versions is that version 2 supports two additional protocol operations (informs operation andsnmpgetbulk query) and one additional object (counter64 object).SNMP version 3 (SNMPv3) is a user-based security model that provides password authentication for user security and encryption for datasecurity and privacy. Three sets of configurations are available for SNMP read/write operations: no password or privacy, passwordprivileges, password and privacy privileges.You can configure a maximum of 16 users even if they are in different groups.Creating a CommunityFor SNMPv1 and SNMPv2, create a community to enable the community-based security in Dell Networking OS.The management station generates requests to either retrieve or alter the value of a management object and is called the SNMP manager.A network element that processes SNMP requests is called an SNMP agent. An SNMP community is a group of SNMP agents andmanagers that are allowed to interact. Communities are necessary to secure communication between SNMP managers and agents; SNMPagents do not respond to requests from management stations that are not part of the community.Dell Networking OS enables SNMP automatically when you create an SNMP community and displays the following message. You mustspecify whether members of the community may only retrieve values (read), or retrieve and alter values (read-write).22:31:23: %STKUNIT0-P:CP %SNMP-6-SNMP_WARM_START: Agent Initialized - SNMP WARM_START.To choose a name for the community you create, use the following command.• Choose a name for the community.CONFIGURATION modesnmp-server community name {ro | rw}Example of Creating an SNMP CommunityTo view your SNMP configuration, use the show running-config snmp command from EXEC Privilege mode.Dell(conf)#snmp-server community my-snmp-community ro22:31:23: %STKUNIT0-P:CP %SNMP-6-SNMP_WARM_START: Agent Initialized - SNMP WARM_START.Dell#show running-config snmp!snmp-server community mycommunity roSetting Up User-Based Security (SNMPv3)When setting up SNMPv3, you can set users up with one of the following three types of configuration for SNMP read/write operations.Users are typically associated to an SNMP group with permissions provided, such as OID view.• noauth — no password or privacy. Select this option to set up a user with no password or privacy privileges. This setting is the basicconfiguration. Users must have a group and profile that do not require password privileges.Simple Network Management Protocol (SNMP) 863
