Learn how to fix ARP Cache issues in VMware. Our VMware Support team is here to help you with your questions and concerns.

Fix ARP Cache Issues in VMware

Did you know that the ARP cache issues in VMware environments can cause connectivity problems between VMs?

These problems can cause network disconnections, leading to task failures and service disruptions. This is why we need to be able to manage and troubleshoot ARP cache issues to maintain a stable network environment.

The ARP table is responsible for mapping IP addresses to MAC addresses, enabling proper communication between devices on a network. When there’s an issue with the ARP table in a VMware environment, a VM may fail to connect to the network, leading to different operational problems.

To diagnose ARP cache issues, we need to list the ARP entries. This can be done using these commands:

arp -a
esxcli network ip neighbor list


The first command displays the ARP table for the local system only. The latter shows the ARP table for the ESXi host.

If you find incorrect entries in the ARP cache, we can clear them to resolve connectivity issues with these commands:

1. Clear a Specific ARP Entry:

   arp -d IPaddress

   We have to replace IPaddress with the actual IP address of the entry we want to remove.
2. Clear All ARP Entries on ESXi Host:

   esxcli network ip neighbor remove

   Use this command to clear the entire ARP table on the ESXi host.

After clearing the ARP cache, we can verify if it has been emptied. When all entries are successfully removed, we will see a message indicating “No ARP Entries Found.”

To repopulate the ARP table, we can use the ping command. Pinging a broadcast IP address can help re-establish the necessary mappings:

ping Ipaddress

However, pinging a broadcast IP address can lead to network congestion and potential security issues. Hence, our experts suggest using this method carefully.

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Conclusion

In brief, our Support Experts demonstrated how to fix ARP Cache issues in VMware.