Wondering how to track duplicate IP addresses in OnApp? Find out how our Support Engineers tackled this issue when one of our customers had the same problem recently.  

Learn how to track down the virtual machine that is using a duplicate IP address with the help of the MAC address of its NIC. Our OnApp Hosting Support Services is here to resolve your queries, big or small.

How to track duplicate IP addresses in OnApp

You can track down the VM responsible for using the duplicate IP address if you have access to the MAC address of its NIC. We recommend doing this with the arping command on the control panel server. For instance:

arping -c 1 121.122.123.124

After that, log in to the MySQL database and run the following query. Remember to replace the MAC address with the one you discovered.

 select*from virtual_machines where id in(Select virtual_machine_id from network_interfaces where mac_address=’00:16:3E:E3:B3:50’);

This will return the VM with that NIC. In case you do not obtain anything helpful after running the query, the IP address may have been added manually, outside of OnApp.

Our Support Engineers would like to point out that the table name has changed in versions 5.4+. In such cases, you will have to resort to networking_network_interfaces. You can also make larger tables more readable by replacing the ‘;’ with \G at the end of MySQL queries. For instance, the following query will result in the IP addresses assigned to more than one VM:

select id,inet_ntoa(address) as "Duplicated IPs",updated_at,user_id,hypervisor_id from ip_addresses where id in (select ip_address_id from ip_address_usages where virtual_machine_id is not null and unassigned_at is null group by ip_address_id having count(*) > 1);

[Looking for further assistance? We are at your service.]

Conclusion

In short, we learned how to easily track down virtual machines using duplicate IP addresses. Bobcares is here to address all your queries, big and small. It is time to leave it to the experts.

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