NetScaler virtual server becomes inaccessible because of IP conflict issue.

Complete the following steps to troubleshoot the issue:

1. Examine if there are any IP conflicts with the virtual server. 

2. Run the following command from NetScaler:
   sendarp all
   This command sends a GARP from the NetScaler which updates the ARP table of the switch causing a reboot/failover which resolves the issue.

3. Examine the following points on the switch (there should only be 1 MAC entry for the IP in the switch):

   • If there are any duplicate MAC entries for the IP on the switch.

   • If there is any MAC entry for the IP on the switch.

Problem Cause

The switch’s ARP table does not get updated automatically after an ARP time-out or certain interval of time.

This can be confirmed by examining the switch logs at the time of the issue and it does not have an ARP entry of NetScaler VIP in the switch.