Windows VMs experiencing intermediate packet drops

Question

We have a infra with few ESXis, few windows Vms and linux VMs. Infra is connected with 1g Network.

We have a issue where windows VM is getting packet drops which result in hang like sutiation and RDP disconnect.

Packet drops is even between the VMs on same VLAN, say there are two VMs on different ESXi in same VLAN it will observer issue of packet drops.

VM1 & VM2 : windows 2022 server

VM3 & VM4 : Linux

VM1 on esxi01

VM2 on esxi02

VM3 on esxi03

VM4 on esxi04

All ESXi have same configuration

All VMs (both linux and windows) are in same vlan

scenario

1. Ping between windows VM : multiple packet drops on both VMs
2. Ping between Linux VM : No Packet drop
3. Ping from windows VM to linux VM : no packet drop
4. Ping from Linux to windows VM : multiple packet drops observed

Note: when VMs are on same Esxi than there is no ping drop

Answer 1

Hello, Thank you for posting in Q&A forum. It seems like that there's something wrong with the inbound direction traffic on ESXi01 and ESXi02. From Windows aspects, I would suggest checking the configuration on ESXi01 and ESXi02 first:

1. Check if the VLAN and TCP related configuration (like MTU) is good.
2. Check if there's any performance issue when issue happens.
3. Check if there's any other middleware that could block the traffic. Moreover, to further troubleshoot this issue, it's recommended to capture network trace on both ends and see where the packet is dropped to narrow down the issue. Hope this answer can help you well. Best Regards,
   Shujun

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Answer 2

Hello,

Due to ping tool is a networking test command with ICMP massage, which might be loss for various reasons. The steps may help as following:

1.    Check network connectivity: Ensure that all physical network connections between the ESXi hosts are secure and properly functioning. Verify that the network cables, switches, and routers are in good condition. 2.    Verify network configuration: Double-check the network configuration on the ESXi hosts and the virtual switches. Ensure that the VLAN configuration is consistent across all ESXi hosts and that the virtual switches are correctly configured to handle the VLAN traffic. 3.    Check for network congestion: Examine the network utilization on the physical switches and routers to identify any signs of congestion. High network utilization can lead to packet loss. Consider monitoring network traffic to pinpoint any potential bottlenecks. 4.    Check virtual switch configuration: Review the configuration of the virtual switches on the ESXi hosts. Ensure that the virtual switch settings, such as NIC teaming, load balancing, and failover, are properly configured. 5.    Verify MTU settings: Check the Maximum Transmission Unit (MTU) settings on the physical network devices, virtual switches, and VMs. Ensure that the MTU is consistent across all components and matches the expected value for your network infrastructure. 6.    Check for network driver or firmware issues: Ensure that the network drivers and firmware on the ESXi hosts are up to date. Outdated or incompatible drivers/firmware can cause network issues, including packet loss. 7.    Check for resource contention: Verify that the ESXi hosts have sufficient CPU, memory, and network resources to handle the workload. 8.    Test with different VM configurations: Try creating new VMs on different ESXi hosts and test the network connectivity between them. This can help determine if the issue is specific to certain VMs or if it affects all VMs on the ESXi hosts. 9.    Monitor network traffic: Use network monitoring tools to capture and analyze network traffic between the affected VMs. This can help identify any specific patterns or anomalies that may be causing the packet loss. Best Regards,
Shujun

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