Article ID: 126457, created on Aug 6, 2015, last review on Aug 6, 2015

  • Applies to:
  • Virtuozzo
  • Virtuozzo containers for Linux
  • Virtual Automation


After configuring SNMP services on a hardware node, snmpwalk gives a timeout querying Virtuozzo MIBs:

# snmpwalk -m SWSOFT-VIRTUOZZO-MIB -v 1 -c public localhost .
    Timeout: No Response from localhost

or error:

# snmpwalk -m SWSOFT-VIRTUOZZO-MIB -v 1 -c public localhost .
Error in packet.
Reason: (genError) A general failure occured
Failed object: SWSOFT-VIRTUOZZO-MIB::vzSWsoft


The following steps can be followed in order to troubleshoot snmpwalk issues:

  1. Ensure all related packages are up to date:

    # pva-setup --install
    # yum update net-snmp
  2. Try to remove PVA SNMP component and check if the issue is reproduced with default SNMP MIBs:

    # snmpwalk -v 1 -c public .1
  3. Try to use different protocol versions:

       -v 1 | 2c | 3
              Specifies the protocol version to use: 1 (RFCs 1155-1157), 2c (RFCs 1901-1908), or 3 (RFCs 2571-2574).  The default is typically version 3.   Overrides  the  defVersion
              token in the snmp.conf file.
  4. Try to use default configuration files in /etc/snmp directory, in case they have been customized.

  5. SNMP is highly dependent on communication over localhost, so make sure that:

    • there are no prohibiting rules in iptables
    • there are no prohibiting rules in TCP wrappers /etc/hosts.deny and /etc/hosts.allow
  6. Collect and analyze the debug output:

    # snmpwalk -D all -m SWSOFT-VIRTUOZZO-MIB -v 1 -c public . > snmpwalk.log 2>&1   

    An example of a failure identified from a debug log:

    dumpv_recv:                                ObjID: SWSOFT-VIRTUOZZO-MIB::ipAddrEntAddress.
    trace: snmp_pdu_parse(): snmp_api.c, 4682:
    dumph_recv:                             Value
    trace: _sess_process_packet(): snmp_api.c, 5445:
    sess_process_packet: received message id#0 reqid#1374564632
    trace: _sess_process_packet(): snmp_api.c, 5448:
    sess_process_packet: parse fail

    The output shows that snmpwalk could not parse the packet with details about IP address.

  7. Use tcpdump to capture communication on localhost, port 161 (UDP port used by SNMP), and analyze the output:

    # tcpdump -X -nn -i lo port 161 > snmpwalk.tcp.log & snmpwalk -m SWSOFT-VIRTUOZZO-MIB -v 1 -c public localhost . ; sleep 1 ; kill %1
  8. Use strace to capture the work of snmpd and vzsnmpd services:

    • Obtain the PIDs of the corresponding processes

      # ps aux | grep snmp | grep -v grep
      root      614432  0.0  0.0 155432  4692 ?        Sl   Jul30   0:19 /opt/pva/snmp/vzsnmpd
      root      645374  0.0  0.0 120344   828 ?        S    Jul30   0:08 /usr/sbin/snmpd -Lsd -Lf /dev/null -p /var/run/snmpd -a
      root      645433  0.0  0.0 155348  4664 ?        Sl   Jul30   0:19 /opt/pva/snmp/vzsnmpd
    • Run strace for snmpd and vzsnmpd (separately) and reproduce the issue:

      # strace -vvvttTfs1024 -p 645374 -o snmpd.log & strace -vvvttTfs1024 -p 614432 -p 645433 -o vzsnmpd.log & snmpwalk -m SWSOFT-VIRTUOZZO-MIB -v 1 -c public localhost .  ; killall strace

Search Words

Failed object: SWSOFT-VIRTUOZZO-MIB::vzSWsoft

Timeout: No Response from localhost


Reason: (genError) A general failure occured

Error in packet.

319940068c5fa20655215d590b7be29b 2897d76d56d2010f4e3a28f864d69223 0dd5b9380c7d4884d77587f3eb0fa8ef d02f9caf3e11b191a38179103495106f e8e50b42231236b82df27684e7ec0beb

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