Questions tagged [authentication]

Questions about authenticating wireless connections, SSH keys, or passwords in Ubuntu.

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311 votes
10 answers
453k views

How can I set up password-less SSH login?

I want to be able to login to a remote via ssh without having to enter the password all the time. How do I set it up? Is a different command required to execute a password-less session?
Oxwivi's user avatar
  • 17.8k
120 votes
4 answers
132k views

How do I deal with "unauthenticated sources" errors in the Software Center?

Any install that I'm trying through the Software Center is telling me: Requires installation of untrusted packages: The action would require the installation of packages from not authenticated ...
b. e. hollenbeck's user avatar
45 votes
6 answers
128k views

How to run an application using sudo without a password?

... but still be required for applications that need admin privilegies? In order to allow the following: $ apache2ctl restart httpd not running, trying to start (13)Permission denied: make_sock: ...
tutuca's user avatar
  • 2,672
199 votes
6 answers
239k views

Why am I getting authentication errors for packages from an Ubuntu repository?

I'm experimenting with VPNs, so I wanted to install pptpd. john@desktop:~$ sudo apt-get install pptpd [sudo] password for john: <snip> The following extra packages will be installed: bcrelay ...
John's user avatar
  • 3,937
27 votes
7 answers
84k views

"Software can't be installed or removed because the authentication service is not available. "

I have 12.10 ubuntu and when I try to remove / install programs I get notification : Software can't be installed or removed because the authentication service is not available. (org.freedesktop....
grr's user avatar
  • 271
22 votes
5 answers
23k views

I deleted the "/etc/passwd" file and cannot log in

I was trying to change my username and also my home directory (/home/username) and my system started to crash. I deleted the passwd file but I had a backup named passwd_bkp. I tried to rename this ...
joao rodrigo leao's user avatar
50 votes
3 answers
215k views

Can't SSH in as root

I'm using the default installation of openssh-server for my Ubuntu 14.04 server. I can connect through the console as root like normal, with my username and password. When I try to SSH with the same ...
vaindil's user avatar
  • 928
14 votes
5 answers
25k views

Retrieve Windows 8 Product Key from mainboard

My new laptop came preinstalled with Windows 8. Naively, as I am, I just formatted the harddrive and installed fine old Ubuntu. Now I want to install Windows 8 for dual boot again, but I have no DVD ...
Gregor Weber's user avatar
30 votes
4 answers
39k views

Google authenticator for desktop

Is there a desktop application for Google authenticator (an equivalent to the phone app, not the PAM lib)?
raphink's user avatar
  • 1,100
23 votes
9 answers
45k views

ssh no longer allows public key authentication

My machine recently stopped accepting incoming public key authentication. I have an ubuntu 11.04 desktop that I ssh into from a windows machine. I use putty with pageant. I am able to connect but ...
Andrew Redd's user avatar
  • 2,157
11 votes
1 answer
12k views

Unable to disable password authentication over SSH

I configured login by SSH key which is working but I can still login by password, which I don't want. I used sudo nano /etc/ssh/sshd_config to make the following changes: PasswordAuthentication no ...
Mário Alves's user avatar
9 votes
3 answers
27k views

Change default user for authentication

When I attempt to perform certain actions within ubuntu I am asked to authenticate with a root user, but ubuntu doesn't give me options for which root user, it just specifies it as the user that set ...
aplassard's user avatar
  • 201
2 votes
3 answers
29k views

Cannot authenticate without a password

The problem can be reproduced as follows: When I remove the password of an administrator account, "Log In without Password", I cannot use that account to authenticate. When I do something that ...
ThePiercingPrince's user avatar
8 votes
2 answers
40k views

Wifi only accepts passwords of 5 or 13 characters

Installed Ubuntu 13.04 and when attempting to connecting to a home wifi network, the connect button is only click-able with passwords of 5 or 13 characters. Is there a fix?
Joe Ffoulkes's user avatar
132 votes
2 answers
242k views

How can I allow SSH password authentication from only certain IP addresses?

I'd like to allow SSH password authentication from only a certain subnet. I see the option to disallow it globally in /etc/ssh/sshd_config: # Change to no to disable tunnelled clear text passwords #...
ændrük's user avatar
  • 76.7k
52 votes
1 answer
65k views

Use fingerprint authentication not only for login

I'm on 18.04 and have successfully enabled fingerprint login. I would like to use my fingerprint not only to login but if possible also to: Authenticate in the terminal when I do a sudo command ...
Hendrik's user avatar
  • 623
15 votes
5 answers
23k views

Stop asking for authentication to mount USB stick

My Ubuntu 14.04 is asking for my password to mount or unmount an USB stick. How can I change it, so that the mount is automatic and no password input is required ? This is about mounting arbitrary ...
markus_b's user avatar
  • 251
13 votes
3 answers
11k views

What is the least insecure way to store a password that is used by a script?

I have a Bash script that automatically authenticates with a service using my username and password. The credentials are currently stored as plain text within the script. What precautions should I ...
ændrük's user avatar
  • 76.7k
11 votes
1 answer
16k views

how to setup two factor authentication in Ubuntu for Ubuntu users using Google authenticator?

How to setup two factor authentication in Ubuntu for Ubuntu users using Google authenticator (It can also be setup for non Google accounts)?
Hrish's user avatar
  • 2,343
8 votes
4 answers
75k views

Password not working for sudo ("Authentication failure")

Before I mention anything further, DO NOT give me a response saying that terminal won't show password input. I'm AWARE of that. I'm typing my user password in (not a capslock issue), and for some ...
Souta's user avatar
  • 237
5 votes
2 answers
12k views

How do you configure Netplan on Ubuntu to store 802.1x credentials securely?

In an 802.1x enterprise network, I can use NetworkManager to configure 802.1x parameters, including the password. This all works, but requires storing the password in cleartext. We are trying to use ...
Phillip Remaker's user avatar
2 votes
1 answer
11k views

Ubuntu 12.04 GPG error: http://archive.ubuntu.com precise Release: The following signatures were invalid: NODATA 1 NODATA 2 [duplicate]

I know this is asked often but nothing seems to work for me. Every time I try to update I get the following: sudo apt-get update Get:1 http://archive.ubuntu.com precise Release.gpg Get:2 http://ppa....
Filipe Teixeira's user avatar
0 votes
1 answer
561 views

how can i get past the authentication code stuff if i bought from a used computer vendor [closed]

i bought a computer with Ubuntu from a pawn shop not knowing that it had this OS can someone tell me how i can get past the authenticate code screen because I'm tired of getting the update stuff when ...
user219045's user avatar
82 votes
17 answers
468k views

Trying to do ssh authentication with key files: server refused our key

I'm trying to setup ssh authentication with key files in stead of username/password. The client is a Windows box running PuTTY and the server is a Ubuntu 12.04 LTS server. I downloaded puttygen.exe ...
Forkbeard's user avatar
  • 2,433
33 votes
6 answers
42k views

"Authentication required to refresh system repositories" in Ubuntu 19.10

If one of the users in our group tries to login to his desktop computer, he gets a popup "Authentication required to refresh system repositories". When I type in my administrator password in this ...
bruschino's user avatar
  • 441
20 votes
9 answers
22k views

Access Prompt keeps asking for GMail password

A pop up keeping appearing in Ubuntu (running 12.10), asking for the password to my gmail account. The icon has a silver shield, and it is labeled Access Prompt. The actual window has an image of ...
bigcat42's user avatar
  • 1,101
14 votes
3 answers
56k views

The repository 'http://dl.google.com/linux/chrome/deb stable Release' does not have a Release file

After executing this command sudo apt-get update && sudo apt-get -y upgrade I get this error W: The repository 'http://dl.google.com/linux/chrome/deb stable Release' does not have a Release ...
Eric kioko's user avatar
11 votes
4 answers
118k views

Public Key authentication failed

I am using ubuntu 13.10, and the server runs ubuntu 12.04. I had generate private and public keys using ssh-keygen, and put id_rsa.pub to server side and added it to authorzied_keys accordding to the ...
leetom's user avatar
  • 213
11 votes
3 answers
6k views

Security warning from Facebook in Chromium

I am terrified. Every ten minutes Chromium pops up with a tab stating: Success SECURITY WARNING: Please treat the URL above as you would your password and do not share it with anyone. Very ...
Max Petersen's user avatar
11 votes
2 answers
26k views

Save print server authentication credentials

At my work, I print through a print server. My /etc/cups.d/client.conf file is: ServerName the.appropriate.server.location With this configuration I have to log in with a username and a password ...
Bruno's user avatar
  • 233
9 votes
5 answers
40k views

Installed perfectly but password not working for login or authentication

I installed Ubuntu on an old XP machine (replaced XP with Ubuntu) and it seemed like it went well... Until I tried to download and install the suggested updates! The password I set during installation ...
Nick's user avatar
  • 91
8 votes
5 answers
36k views

Ubuntu 12.04 network printing through Windows Samba server

I have to print through a Samba server sharing an HP printer. After upgrading to 12.04 I'm no longer able to get it to work. The printer is shared through a samba server and I need to provide logon ...
thomas's user avatar
  • 211
7 votes
7 answers
23k views

Gnome/X logs off immediately after login -- which logfiles are relevant?

I've been tinkering with fingerprint-gui as well as X/xrandr resolution settings. When I start my machine, it boots up normally. As soon as X and gnome have finished starting, it logs me off ...
joebuntu's user avatar
  • 333
6 votes
2 answers
3k views

Where should a non-administrative user save a CA certificate?

I have a CA certificate that I use to connect to a WPA2 Enterprise wireless network. Where within my home folder should I store the .crt file? I don't see anything in the Filesystem Hierarchy ...
ændrük's user avatar
  • 76.7k
3 votes
1 answer
2k views

Log file size or age

I'd like to change various log files (particularly auth.log) to retain info for anywhere from the last 30-90 days. Right now it only has about 4 days worth of info. How do I modify these settings ...
Ron's user avatar
  • 31
3 votes
2 answers
9k views

Authentication in wireless network

I am authenticating a network using WPA2, but it's not working (it authenticates then turns off) OS: Ubuntu 13.04 Wireless network card : Intel Corporation Ultimate N WiFi Link 5300 $ dmesg: [ 1248....
Josimar Andrade's user avatar
3 votes
2 answers
3k views

How do I install FreeNX server so that it works correctly?

I've tried every single possible way of installing the server now, I've read every how to available and I still can't get it to work. Please let me know in which step I do wrong. I'm using ubuntu 10....
Niklas's user avatar
  • 1,143
3 votes
1 answer
2k views

ssh localhost issue on Ubuntu 16.04

I am trying to ssh to localhost, but it's asking for a password every time. What I tried: ssh localhost ssh-keygen -t dsa -P '' -f ~/.ssh/id_dsa cat ~/.ssh/id_dsa.pub >> ~/.ssh/...
Amarjeet Chauhan's user avatar
2 votes
1 answer
11k views

Network authentication not working

I just installed Ubuntu 12.04 and Im trying to connect it to my NAS. It connects fine to folders where there are not authentication needed. However, if I try to open a password protected folder it ...
jayfire's user avatar
  • 171
1 vote
1 answer
436 views

syntax error when installing auth_mellon module on Apache

I need to compile the module auth_mellon and I am using autoconf but when I run this command ./configure --with-apxs2=/usr/bin/apxs I am getting this ./configure: line 3138: syntax error near ...
eeadev's user avatar
  • 133
0 votes
3 answers
24k views

How do I enable account lockout using pam_tally?

I am trying to implement account lockout in ubuntu using pam_tally. I have tried adding the follwing lines in /etc/pam.d/common-auth auth required pam_tally.so deny=3 account required ...
nitin's user avatar
  • 101
64 votes
3 answers
74k views

How can multiple private keys be used with ssh?

I was able to setup ssh to use private/public key authentication. Now I am able to do ssh user@server1 And it logs on with the private key. Now I want to connect to another server and use a ...
Joshua's user avatar
  • 895
55 votes
3 answers
6k views

How can I use a passcode generator for authentication for remote logins?

I would like to strengthen the authentication of my SSH logins by adding another factor: a passcode generator device, or a passcode generation application on my mobile phone. The only obvious options ...
Jorge Castro's user avatar
  • 71.7k
42 votes
2 answers
24k views

gvfsd-admin daemon authentication forces me to restart Ubuntu - VERY annoying!

I installed Ubuntu 20.04 on a new partition less than a week ago. I have not yet gotten all the basic stuff to work. But now, from time to time, 20.04 pops up a small window saying "...
Henrik R.'s user avatar
  • 1,049
29 votes
1 answer
2k views

How to know if a authenticate box is real or fake?

For example, someone creates a fake Authenticate dialog to get my root password. How to know if it is real or fake?
user3683331's user avatar
25 votes
1 answer
24k views

Error authenticating some packages while upgrade

When I try to upgrade my ubuntu 13.04 to 13.10, it gives the following error: It was not possible to authenticate some packages. This may be a transient network problem. You may want to try again ...
Singularity's user avatar
23 votes
1 answer
40k views

How do I solve "Incorrect permission on/usr/lib/policykit-1/polkit-agent-helper-1(need to setuid root)"?

I'm getting this error message: "Incorrect permission on /usr/lib/policykit-1/polkit-agent-helper-1(need to setuid root)" Due to this problem I can't download any app.
Akhil George's user avatar
18 votes
6 answers
35k views

Use different username on CUPS remote printing

I'm using CUPS to print on an enterprise network. The job gets submitted fine, but I need to submit it as another username. Now I'm jon but I need to send it as say jonallard. On the command line, ...
jonallard's user avatar
  • 373
17 votes
5 answers
36k views

Can't complete dropbox installation from behind proxy

Problem: My PC on campus sits behind a proxy (requiring authentication) and I can't setup Dropbox. I am convinced that this is a proxy issue as I can't setup Ubuntu one either (but I don't use Ubuntu ...
Mark Jones's user avatar
12 votes
1 answer
8k views

How to smoothly login through openvpn with 2 factor auth?

I have a openvpn set up with 2 factor authentication via Google Authenticator app. In connection details I filled User name and Password (User key password empty). When I login for the 1st time I get ...
WellBloud's user avatar
  • 265