Overview

If you are using the High Availability (HA) feature in Kerio Control and experiencing issues where the slave machine loses all connectivity after the first sync and reboot, this could be due to the VLAN configuration on your ESXi host. This problem is particularly common when using VLAN on the ESXi virtual switch port groups, which are typically used for VLAN trunking. You may also notice that the interface names change on the network list and that you need to enable/disable promiscuous mode on the NIC to restore connectivity.

Solution

To resolve this issue, follow these steps:

1. Review your VLAN configuration on the ESXi host and ensure that it matches the VLAN settings in Kerio Control. 
2. Check the network adapter settings of the slave VM in ESXi. Ensure that the correct network (matching the VLAN settings) is selected and that the adapter is connected.
3. Try disabling the HA configuration for Internet interfaces.
4. If possible, test the HA setup without using VLANs or with a simpler network configuration to see if the issue persists. This could help determine if the problem is specifically related to the VLAN setup.
5. Change the VMware ethernet driver from VMXNET3 to E1000. This could make it more compatible with Kerio Control's HA feature, especially in complex networks with VLANs. It handles these setups more effectively, solving the intermittent connectivity issues.

Summary

Issues with the High Availability (HA) feature in Kerio Control, particularly when the slave machine loses all connectivity after the first sync and reboot, can often be resolved by adjusting the VLAN configuration on your ESXi host and changing the VMware ethernet driver from VMXNET3 to E1000.

FAQ

1. How can I resolve connectivity issues with the slave machine in Kerio Control's HA setup?
   Changing the VMware ethernet driver from VMXNET3 to E1000 can help resolve these issues.