Troubleshooting VMware vSphere ESXi Virtual Machine TCP/IP ping connection issues

Products

VMware vSphere ESXi

Issue/Introduction

This article provides steps to troubleshoot virtual machine (VM) network communication problems over a TCP/IP network protocol, such as with the ping command.

Note: ESXi does not log VM connectivity or communication (outside of port or physical link failures seen at the host level), so it is important to perform the troubleshooting steps in this article during the time you are experiencing the issue to be able to determine the cause.

Symptoms:

A virtual machine will not ping.
A TCP/IP connection fails to and from a virtual machine.
Cannot establish a TCP/IP connection. For example, a virtual machine is no longer pingable or cannot ping other virtual machines.

Resolution

Note: Validate that each troubleshooting step is true for your environment. These steps provide instructions or a link to a document, for validating the step and taking corrective action as necessary. The steps are ordered in the most appropriate sequence to isolate the issue and identify the proper resolution. Do not skip a step.

Troubleshooting virtual machine TCP/IP connection issues

Check the VM's network configuration in the guest OS and verify TCP/IP functionality. For more information, see Verifying virtual machine TCP/IP settings (1007875).
Check for duplicate IP addresses and resolve TCP/IP driver issues. For more information, see Resolving virtual machine IP address conflict issues (1008177).
Ping another VM that is on the same host and in the same port group on that host.
1. If pings to another VM on the same host same port group are not successful, then the issue is within the VM itself (in the guest OS or VM adapter settings).
  1. Next ping the loopback address to verify that TCP/IP is working correctly. For more information, see Troubleshooting virtual machine TCP/IP issues by pinging the loopback address (1008206).
  2. Check firewall configuration. For more information, see Troubleshooting network connection issues caused by firewall configuration (1007911).
2. If pings to another VM on the same host same port group are successful, then the issue usually lies in the port group's configuration or in the physical networking. Continue following the troubleshooting steps below.
  1. Verify the default gateway and try to ping it. For more information, see Troubleshooting virtual machine default gateway connection issues (1007910) .
    
    Note: If connection to the default gateway is successful, but connections to other subnets are unsuccessful, then there is an issue in routing/Layer 3. Contact your network team to determine why the Layer 3 connections are failing.
  2. You can also check the esxtop output using the n option (for networking) to see which pNIC the virtual machine is using. Try shutting down the ports on the physical switch one at at time to determine where the virtual machine is losing network connectivity. This also rules out any misconfiguration on the physical switch port(s).
  3. Check the virtual switch VLAN configuration. For more information, see VLAN configuration on virtual switches, physical switches, and virtual machines (1003806).
  4. Clear the Address Resolution Protocol (ARP) cache.
  5. Verify physical switch port security. For more information, see Loss of network connectivity when Cisco port security is configured on the physical switch.
If the above troubleshooting does not find the answer, use the pktcap-uw tool to packet capture on the physical NIC or on the VM adapter. For more information, see Using the pktcap-uw tool in ESXi 5.5 and later (2051814).

Note: ESXi does not log VM connectivity or communication (outside of port or physical link failures seen at the host level), so it is important to perform the troubleshooting steps in this article during the time you are experiencing the issue to be able to determine the cause.

Additional Information

For more troubleshooting information, see: