Ошибка sudo unable to resolve host

Kit SundeKit Sunde

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

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

2. 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.

Edit /etc/hosts and append your new hostname to the 127.0.0.1 line (or create a new line if you prefer that).

Mine looks like:

127.0.0.1       localhost localhost.localdomain penguin

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

Replace penguin in the above example by your new hostname as stated in the /etc/hostname file.

Add your hostname to /etc/hosts like so:

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

answered Sep 15, 2014 at 16:03

Note, this is an answer to this question which has been merged with this one.

Your hostname (dave00-G31M-ES2L) is not represented in /etc/hosts. Add an L to this line:

127.0.1.1   dave00-G31M-ES2

So it becomes:

127.0.1.1   dave00-G31M-ES2L

In order to accomplish this, open a console (press Ctrl+Alt+T) and type:

sudo gedit /etc/hosts

Add the letter L as mentioned, save and exit.

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!

answered Apr 1, 2013 at 1:18

I was having the same issue even though the hostname in my /etc/hostname file and /etc/hosts file matched.

My hostname was «staging_1». It turns out that you can’t have an underscore in your hostname, which is why I was getting this error. Changing the underscore to a hyphen fixed my problem.

answered Aug 13, 2014 at 13:50

answered Jan 15, 2015 at 5:15

The symptom given in the question may correlate strongly with this more specific problem:

$ hostname --fqdn
hostname: Temporary failure in name resolution

There are different ways that this could be resolved, one of which is to add your hostname as localhost in /etc/hosts (as shown in several other answers). This may be the right thing to do in general, but it isn’t the only possible resolution.

A «fully qualified domain name» may be supplied by an external DNS server or similar (if such is available on your network). In this case, sudo will not complain, despite the missing entry in /etc/hosts.

Note: sudo attempts to dereference the hostname, even though it isn’t necessarily required, due to optional capabilities in the sudoers file. See sudo command trying to search for hostname.

As long as the delay isn’t too long, this error message is typically harmless.

answered Sep 18, 2017 at 22:17

dashohoxhadashohoxha

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user93581user93581

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Some terminal emulators will not update prompt with the correct hostname until you close and restart the emulator (lxterminal, I’m talking to you).

I spent 30min fighting with this error after editing my hostname and hosts files and running sudo service hostname restart until I ran sudo hostname and saw that the hostname was the new value, even though the prompt was showning the old value.

answered Jun 19, 2016 at 16:29

XandruCeaXandruCea

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Sorry I can’t help you much but, since it says «can’t resolve host» try running:

hostname

And see if the output is the hostname of the machine. If not, the problem is the host configuration, not sudo.

answered Aug 31, 2011 at 19:16

M.G.M.G.

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answered Aug 24, 2016 at 15:07

SynthSynth

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I had the same problem. I solved it by editing the /etc/hosts and /etc/hostname files… on the /etc/hosts file, just edit the top part as shown below.

#vi /etc/hosts
    127.0.0.1   localhost
    127.0.1.1   localhost  myhostname




#vi /etc/hostname
    myhostname

tanmoytanmoy

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This issue is caused by not enabling enableDnsHostnames in your VPC configuration.

enableDnsHostnames

Indicates whether the instances launched in the VPC get DNS hostnames. If this attribute is true, instances in the VPC get DNS hostnames; otherwise, they do not. If you want your instances to get DNS hostnames, you must also set the enableDnsSupport attribute to true.

http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-dns.html#vpc-dns-updating

SamAkoSamAko

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arntgarntg

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answered May 31, 2016 at 23:22

answered Feb 9, 2018 at 3:06

Bhavesh OdedraBhavesh Odedra

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Yevgeniy BrikmanYevgeniy Brikman

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I’ve had a similar case to @bhavesh-odedra’s. My storage usage was 100%, I extended it to 5Gb more, restarted instance with sudo reboot and after that I started getting this error.

I checked disk usage with sudo df -h and found out that my Ubuntu system is not aware of extended storage. Rebooting again did not help.

I checked answers on this page. DNS hostname was Enabled in AWS VPC configs. Then I added private IP to /etc/hosts — it did not help too.

After some time and I decided to reboot instance using AWS console (not sudo reboot). I don’t know whether AWS console informed my system that new storage is ready for use or something else happened, but then with sudo df -h I’ve convinced that my new storage space was in use. After that the error disappeared.

answered Nov 3, 2022 at 9:12

answered Nov 14, 2019 at 9:52