You can use SNMP to configure the SNMP agent on the Citrix ADC appliance to generate asynchronous events, which are called traps. The traps are generated whenever there are abnormal conditions on the Citrix ADC. The traps are then sent to a remote device called a trap listener, which signals the abnormal condition on the Citrix ADC appliance. Or, you can query the SNMP agent for System-specific information from a remote device called an SNMP manager. The agent then searches the management information base (MIB) for the data requested and sends the data to the SNMP manager.

The SNMP agent on the Citrix ADC can generate traps compliant with SNMPv1, SNMPv2, and SNMPv3. For querying, the SNMP agent supports SNMP version 1 (SNMPv1), SNMP version 2 (SNMPv2), and SNMP version 3 (SNMPv3).

For information about SNMP parameters, traps, and its descriptions, see Citrix ADC SNMP OID Reference.

The following figure illustrates a network with a Citrix ADC that has SNMP enabled and configured. In the figure, each SNMP network management application uses SNMP to communicate with the SNMP agent on the Citrix ADC. The SNMP agent searches its management information base (MIB) to collect the data requested by the SNMP Manager and provides the information to the application.



The SNMP module in a Citrix ADC appliance supports a maximum length of 128 bytes (as compliant with RFC 3416) for an SNMP OID. A long index variable name for an object can result in an SNMP OID exceeding 128 bytes in length.

To resolve this issue, the Citrix ADC SNMP module supports a maximum length of 31 characters for an index variable name. If an index variable name exceeds 31 characters in length, the SNMP module using an hash algorithm converts the name to a 31 characters hash value. This hashed value is used in the SNMP OID for that variable.

The original index variable name is stored in another variable, which has the following name format: <variable type>FullName. For example, When the name of a load balancing virtual server has more the 31 characters, vserverName SNMP OID contains the hashed value and vsvrFullName SNMP OID contains the full (original) name of the virtual server.

Similarly, for SNMP traps, the index variable displays a hashed valued. <variable type>FullName, which stores the full name of the original index variable name, is also part of the trap messages.

Importing MIB Files to the SNMP Manager and Trap Listener

To monitor a Citrix ADC appliance, you must download the MIB object definition files. The Citrix ADC appliance supports the following enterprise-specific MIBs:

  • A subset of standard MIB-2 groups. Provides MIB-2 groups SYSTEM, IF, ICMP, UDP, and SNMP.
  • A system enterprise MIB. Provides system-specific configuration and statistics.

You can obtain the MIB object definition files from the /netscaler/snmp directory of the Citrix ADC appliance or from the Downloads tab of the GUI.