Configuring Error Conditions

Overview
Configuring Error Conditions
Examples

Overview

The SNMP Agent Simulator allows you to configure an SNMP agent to send invalid responses. The intention is to test the SNMP manager's robustness in the face of receiving bad packets. The feature Error Simulation allows you to simulate error conditions and scenarios by which you can send errors for the requests received. The errors can be thrown for all the three type of requests : GET, GetNext, and Set.

All the error conditions will be reflected only at agent run time and will not be saved in the simulator. You can define the type of error that an OID should respond with, when queried.

To simulate errors, do the following :

Choose Configure -> Error Simulation in the menu bar. The Simulate error dialog appears with the MIB tree loaded.
Select the OID from the MIB tree. In case of tables, the instance can be selected from "Select the Instance" dialog, which pops up when the Add button is clicked.
Choose the error type that you want to specify from the options. The error types are

tooBig

noSuchObject

noSuchInstance

endOfMibView

badvalue

readOnly

genErr

noAccess

You have to specify the condition on which you want to simulate this error. You can choose one or all the conditions. The condition are as follows :

Get Request

Get Next Request

Set Request

Click Add to add the OID, error type, and condition to the list.
To modify any of the parameters in the list, select an entry from the list, modify the parameters, and click Modify. The entry will be modified.
To delete an entry, select the entry form the list and click Delete.

Note:

1. While doing GETNEXT / SNMPWALK the nodes for which the error is configured will be skipped .

2. You can specify only one type of error at an instance.

Examples

Assume that the Simulated agent with RFC1213 MIB is started. You can configure the following sample error conditions in the SNMP Agent Simulator and test the same from the MIB Browser.

In the error simulation dialog, select the node "SysDescr" under system group, choose the error type as "readOnly" , specify the error condition as "Set Request" and click Add. When a SET request is made from the Mib Browser on the SysDescr node, the agent will respond with "readOnly" error.
In the error simulation dialog, select the Table node "ifDescr" in the ifTable , choose error type as "noSuchInstance", specify the error condition as "Get Request", and click Add. Specify an instance from the list of instances. When a GET request is made from the Mib Browser for the specified instance, the agent will respond with "noSuchInstance" error.