Error message “sudo: unable to resolve host (none)”

Two things to check (assuming your machine is called my-machine, you can change this as appropriate):

That the /etc/hostname file contains just the name of the machine.

That /etc/hosts has an entry for localhost. It should have something like:

 127.0.0.1    localhost.localdomain localhost

 127.0.1.1    my-machine

If either of these files aren't correct (since you can't sudo), you may have to reboot the machine into recovery mode and make the modifications, then reboot to your usual environment.

4 years ago

Add your hostname to /etc/hosts like so:

echo $(hostname -I | cut -d\  -f1) $(hostname) | sudo tee -a /etc/hosts

4 years ago

I had this issue when I was using ubuntu on a VPS. I solved it editing /etc/hosts file.

run this command:

sudo nano /etc/hosts

and then add:

127.0.0.1   localhost.localdomain localhost

127.0.1.1   ubuntu

I hope that will solve your issue :)

PS: Remember to reboot your computer!

4 years ago