Analysis

Use the following checklist when no response is received from an agent:
  1. Is the SNMP agent running?
  2. Is a path to the agent available? Try issuing a PING request to the IP address of the agent.
  3. What is the timeout value? For example, the timeout value on the snmp command defaults to three seconds. Trying the request again with a larger timeout value, such as 15 seconds, might result in an answer.
  4. Does the request use the correct port number and IP address?
  5. Were any errors reported at the SNMP agent when the variable was requested?
  6. If community-based security is being used, is the correct community name (including correct case) being used in the request?
  7. Is the community name defined for the IP address from which the request originates? For example, a community name defined only for IPv4 addresses is not be usable from an IPv6 address.
  8. Is the community name defined for the SNMP version of the request? If the PW.SRC file is being used for community name definitions, community names are usable for both SNMPv1 and SNMPv2c requests. If the SNMPD.CONF file is being used for community name definitions, separate definitions are required to allow the use of the community name for both SNMPv1 and SNMPv2c requests. Note that the snmp command defaults to sending SNMPv1 requests. To send an SNMPv2c request using the snmp command, an entry is required in the OSNMP.CONF file and the snmp command must be issued with a -h value that refers to an entry in the OSNMP.CONF file.
  9. Does the agent support the SNMP version of the request? The z/OS® Communications Server supports SNMPv1, SNMPv2c and, if configured with SNMPD.CONF, SNMPv3.
  10. Are you using SNMPv3 with Advanced Encryption Standard (AES) encryption for the privacy protocol? For AES encryption, the z/OS Integrated Cryptographic Service Facility (ICSF) must be active. For detailed information about configuring ICSF, see z/OS Cryptographic Services ICSF Administrator's Guide.

If the problem still occurs after checking the preceding items and making any needed changes, obtain SNMP agent level seven trace output documentation.

Check the following in the SNMP agent traces:
  1. Was the SNMP request PDU received by the agent?
  2. Did it have a valid community name? Note that community name is case-sensitive and mixed-case.
  3. Was the IP address of the manager the expected IP address?
  4. Was an SNMP GetResponse-PDU sent back to the manager?
  5. Was an AuthenticationFailure trap generated?
    Guideline: For these traps to be generated, you must first provide the trap destination information in either the SNMPTRAP.DEST or SNMPD.CONF file. Then, provide OSNMPD.DATA information where the snmpEnableAuthenTraps MIB object is set to 1, to enable the authentication traps. For detailed information about enabling traps, see z/OS Communications Server: IP Configuration Reference.
The following documentation might also be needed in some cases, but contact the IBM® Software Support Center before this documentation is obtained:
  • Dump of SNMP agent address space
  • Dump of the TCP/IP address space (for TCP/IP and TN3270E Telnet subagent problems)
  • Dump of OMPROUTE address space (for OMPROUTE subagent problems)
  • Dump of Network SLAPM2 subagent address space (for Network SLAPM2 subagent problems)

Information about obtaining a dump can be found in z/OS MVS Diagnosis: Tools and Service Aids. Obtaining SNMP traces is discussed in SNMP traces.

Parent topic: No response from the SNMP agent