First, collecting synchronized network logs on NetScaler, VDA and Client.

For CVAD, Client will build the connection with NetScaler with port 443, NetScaler will connect VDA port 1494/2598.

So filter the network logs with these port to find more details.

Here is an example, VDA cannot build UDP session via NetScaler but it is normal if not go through the NetScaler.

1. In the NetScaler network trace, it shows NetScaler has send the UDT handshake packets to VDA, but VDA no response, then it transfer to TCP.
2. In the VDA network trace, there is no UDT packets from NetScaler, only having TCP packet . So the UDT packet is not sent to the VDA.
3. Back to NetScaler network trace, finding the MAC address of the next hop node, then ask customer to check this node.
4. Finally customer confirmed that an intermediate network device blocked the UDP packet, issue fixed after allow UDP packet in this intermediate network device.

Many customers will use NetScaler as gateway to build their environment.

Sometimes network-related issues require collaboration between engineers from both sides.