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NSX Manager detecting duplicate of it's own IP (2150466)

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  • NSX Manager detecting duplicate of it's own IP with MAC.

  • There are no duplicates in the environment.

  • In the NSX Manager system events, you see alerts similar to: 

    Detect_Duplicate_NSXIP: .! 50% packet loss
    Detect_Duplicate_NSXIP: output of arping command 0
    Detect_Duplicate_NSXIP: Duplicate IP Detected
    fcron[25252]: Job '/blue_lane/bin/' completed
    Detect_Duplicate_NSXIP: The following mac has the same IP as NSX Manager
    Detect_Duplicate_NSXIP: Sending MAC Address

  • In the /var/log/messages file, you see alarms every day similar to: 

    [var/log]# egrep -R -i "is duplicate" *
    messages:2017-02-16T18:05:00+00:00 XXXX Detect_Duplicate_NSXIP: Detecting If the NSX manager IP  xx.xx.xx.xx  is duplicate


This issue occurs when arp command starts responding for the NSX Manager IP though the IP is not assigned to any other machine in the network. Therefore, NSX Manager starts sending a false alarm indicating that the NSX Manager IP is duplicated in the network.


This issue is resolved in NSX for vSphere 6.3.0, available at VMware Downloads.

To work around the issue if you do not want to upgrade, complete these steps:

  1. Log in to the NSX Manager.

  2. Run the  vi /etc/fcrontab command and comment out script line by adding # in front of the line.

    [root@/var/log]# cat /etc/fcrontab
    @ 1 /usr/sbin/logrotate /etc/logrotate.conf
    @ 1 /blue_lane/bin/
    10 0 * * * secureall /home/secureall/secureall/sem/WEB-INF/classes/  -p 2>&1 | /usr/bin/logger -t  Run_AI_Purge
    */5 * * * * /blue_lane/bin/ >> /var/log/rabbitstatus.log
    #* */3 * * * /blue_lane/bin/ 2>&1 | /usr/bin/logger -t Detect_Duplicate_NSXIP

  3. Reload the new configuration to cron by running this command:

    >fcrontab /etc/fcrontab

    2017-02-17T10:57:32+00:00 fcrontab[22653]: installing file /etc/fcrontab for user root
    2017-02-17T10:57:32+00:00 fcronsighup[22654]: Conf file (/usr/local/etc/fcron.conf) must be owned by root:fcron and (no more than) 644 : ignored
    2017-02-17T10:57:32+00:00 fcron[3528]: updating configuration from /usr/local/varr/pool/fcron
    2017-02-17T10:57:32+00:00 fcron[3528]: adding new file root"
    2017-02-17T10:57:38+00:00 fcron[23251]: Job '/usr/sbin/logrotate /etc/logrotate.conf' started for user root (pid 23252)
    2017-02-17T10:57:38+00:00 fcron[23253]: Job '/blue_lane/bin/' started for user root (pid 23254)
    2017-02-17T10:57:40+00:00 fcron[23251]: Job '/usr/sbin/logrotate /etc/logrotate.conf' completed

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