how to remove "open dns" from imac

There are programs that are installed the have no uninstall. Taking the app out of applications, emptying trash and restarting does not get rid of it. OpenDNS really should be reclassified as malware. Any way, OpenDNS has been totally unresponsive to email requests for instruction. Any suggestions?

Go to System Preferences - Network - Advanced - DNS & remove any numbers in the DNS servers field.

If you changed the settings in your router/modem : check the manual to see how to change it back again.

Go to Systems preferences > Network > and in the panel to the right are the various DNS options you have. Remove what you need to and either replace or stay with what is left.

Unlock the Network preference pane, if necessary, by clicking the lock icon in the lower left corner and entering your password. Cllck Advanced, open the DNS tab, and delete the server addresses. Click OK and then Apply.