Unable to ping virtual machines even though there is network connectivity

 Symptoms

• RDP sessions to virtual machines drop intermittently
• RDP sessions to virtual machines fail despite proper network connectivity
• When you continuously ping virtual machines that reside on the same host, you see that the virtual machines drop 8 to 10 packets at the same time
• When you continuously ping virtual machines that reside on different ESX hosts, you see that the virtual machines drop packets but at different times

Resolution

Windows guest operating systems poll CD devices frequently. When multiple virtual machines try to access a single physical CD drive, it impacts the performance.

To improve the performance, you can disconnect the CD devices in virtual machines when they are not required.

To disconnect the CD-ROM drives using GUI:

1. Right-click the virtual machine and click Edit settings.
2. Click CD/DVD Drive.
3. Deselect Connected and Connect at power on under Device Status on the right side.
4. Click OK.

To disconnect the CD-ROM drives using CLI:

1. Log in to your ESX host as root either by using an SSH session or directly from the server console
2. Navigate to the /vmfs/volumes/Datastore_Name/VM_Name folder of the virtual machine
3. Open the virtual machine configuration file using a text editor and search for the entry:
   
   ideN:N.startConnected = "TRUE"
   
4. Change the entry to:
   
   ideN:N.startConnected = "FALSE"
   
5. Save the changes.

Note:

• The virtual machine configuration file is required to be reloaded for changes to take in effect. For more information, see Reloading a vmx file without removing the virtual machine from inventory (1026043).
• Alternatively, migrate the virtual machine to another host.