NetScaler VPX loses network connectivity intermittently on VMware ESXi after upgrading to version 12.0 Build 53.x to 12.0 Build 57.x and version 11.1 build 54.x to 11.1 Build 58.x.

• It has been observed that VPX loses connectivity during snapshots or during backups
• Interface will start flapping followed by the network connectivity being lost
• Interfaces on VPX will NOT show HANG or STALL
• RESET interface or reboot of the NetScaler will bring the connectivity back for few minutes
• Adapter type on VMware is E1000

This is a known issue and will be fixed in the following NetScaler releases:
12.0 Build 58.x
11.1 Build 59.x

Workaround

Complete the following steps to workaround this issue:

1. Remove all the E1000 interfaces.
   Note: Not just disconnect interfaces but remove all the E1000 interfaces. E1000 and VMXNET3 cannot co-exist.
2. Change the adapter type from E1000 to VMXNET3 VMware ESXi.
3. Ensure to use the same MAC address as mentioned in the license to avoid license re-allocation. If using the same MAC address does not help with license, then re-allocation of license is required.

   

Problem Cause

Rx ring was cleaned completely as a part of every reset which is not in sync with backends expectation.