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Questions tagged [authentication]

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

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13 views

When I try to use Login Window in Cinnamon's System Setting, it keeps showing a authentication popup and never let me get in

I recently installed Cinnamon on my Ubuntu 18.04. And, it seems running right. Today, I tried to change a background pic for its login session. I researched online, and I installed lightdm-settings by ...
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19 views

Multiple Subdomains with different ssh host keys (docker containers)

I am trying to get rid of these annoying message Warning: the ECDSA host key for 'mysub.domain.de' differs from the key for the IP address 'XXX.XXX.XXX.XX' Offending key for IP in /home/thisuser/.ssh/...
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1answer
23 views

SSH Login Via Keyfile With No Local Password

I have my remote SSH setup with my public key so I can login with it. This is great; however, I still have to type the password for my private key file. How can I login using the keyfile and no ...
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16 views

Proxy server with authentication

I want to create a proxy server that will check if user is authenticated (e.g. in database) and if not send him to custom captive portal when he can log in. And if user is authenticated just pass him ...
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47 views

Weird behaviour about password prompts and permissions in Lubuntu 18.04

I am having a strange behaviour with Lubuntu 18.04 fully updated machine. I try to use software application (system tools -> software) to install some application. Say for example Raincat. When I ...
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1answer
212 views

why wget does not use userName and password in URL first time

Below is the command and response of wget, It first time does not use provided userName and password and get 401, later it uses the auth and gets 200. This works well with curl but same thing happens ...
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0answers
25 views

Join ubuntu 16.04 machine to windows active directory domain using PBIS

I was using PBIS to join ubuntu machine to windows domain. Before running the domainjoin-cli command to join to windows domain, I have to specify the domainname, ip address of windows domain in the "...
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41 views

Ubuntu 18.04: Authentication is required - no drop down menu in order to select admin user

We are two admins in the network, and on each computer that we install Ubuntu we have set our own user. Each PC has the following users: admin1,admin2,desktop_user. When I try to install something ...
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185 views

pam config issue ( bad jump )

After some packages/data got corrupted, I ran fsck and repaired the packages from the recovery console. As far as I can tell all packages should be whole and apt does not complain. However - I cannot ...
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41 views

Migrating servers

For my sins I am assisting a friend in migrating from a 10 year old SuSE mail server to one running Ubuntu-18.04. One of the things I need to do is migrate over about a dozen or so users--several of ...
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1answer
268 views

A lot of PAM authentication errors on my logs targeting my mailserver. How do I stop it?

I need help pinpointing some errors in my auth.log file on my Ubuntu server. A few weeks ago, I found a plethora of login attempts to my SSH port (22) on auth.log, so I changed my SSH port. It was ...
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213 views

Integrate Ubuntu 18.04 box with one AD domain and user with other AD domain

I will try to explain my problem as simple as I can. I have the following problem: Our organization has two Active Directory forests, in one hand computer.forest.com has the computer objects, in the ...
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0answers
81 views

Upgrade from 12.04 to 14.04 via proxy server

We're attempting to upgrade our Ubuntu 12.04 system to 14.04. Our internet connection for the Linux server goes via a proxy server that requires authentication. From a putty session I've been able ...
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1answer
482 views

Fingerprint-GUI login ISSUE with new 18.04 LTS

This exact same question was asked here but the community missread and marked inacurately as a duplicate. fingerprint-gui and 18.04 login issue I am also NOT asking HOW TO install. I am asking ...
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1answer
158 views

Not able to connect to GitHub via proxy

Not sure if this question belongs in this forum but I'll give it a chance. I'm trying to connect my Ubuntu with GitHub via a proxy so I can clone repositories via the git command. I've followed the ...
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0answers
49 views

Wifi working on band 5 but not 2.4

I have recently installed Ubuntu for the first time ever on an old laptop and it went mostly well. A couple of days ago I dug out another old laptop and installed Ubuntu 16 LTS desktop (32 bit this ...
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36 views

ssh'ing from one computer to another on same subnet with rsa authentication

I have two computers on the same subnet and am trying to ssh from one to the other. I have no problem logging in back and forth with passwords, but I want to use rsa or dsa authentication. I have ...
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2answers
521 views

Ubuntu 18.04 LTS Samba vs Windows 10 Pro

I'm trying to access Samba share using IP address in URL (\\IP_address)from two Windows 10 clients. One physical and one virtual. The physical is on same subnet as Ubuntu server, virtual is Hyper-V ...
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1answer
44 views

How to only make one user authenticate via SSH keys and allow password authentication to all others

I was wondering if it would be possible to only force SSH key based authentication to one user (admin) and allow all other users on the system (excluding root, who's ssh login is already disabled in ...
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33 views

Ubuntu 14.04 login screen disappeared

I had problem logging in and I clicked on a icon and "Debian windows" (It has a Debian logo swirl on a gray background). This new format took over and now I can't get back to the regular Ubuntu format ...
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29 views

ubuntu slow on ssh/sftp connecton

I recently purchased vps server with ubuntu. when i test it worked file. but now i found a problem.. after i worked about 1hours it gets slows down while connecting/authentication to server. ...
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1answer
831 views

fingerprint-gui and 18.04 login issue [duplicate]

I installed fingerprint gui in my laptop having Ubuntu 18.04. But I am not able to login using fingerprint while in terminal using sudo commands it is working fine but for login it is not working.
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1answer
129 views

Git asking for private key?

I'm on Ubuntu and I'm learning how to use Git collaboratively. I have created a pair of public/private keys on my local Ubuntu desktop with the following command: ssh-keygen -b 2048 I then accessed ...
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0answers
64 views

Track all process activity in real or near real time on Linux

I want to track the activity of processes. For processes, forks, file access, etc. should be tracked. Also files, data transfers, authentication events, authorization events, and similar. It should ...
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1answer
320 views

su: Authentication Failure, stopped working

I recently installed Ubuntu 18.04. I used su command, entered my accounts password. It worked successfully for few times. Then I got Authentication Failure, now I'm not sure if I entered wrong ...
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1answer
108 views

Where is my private key?

I was following this tutorial to generate and assign a key to one of my servers, but before running ssh-copy-id -i ~/.ssh/mykey user@host I was tring to find my private key and guess what I can't find ...
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0answers
47 views

How do I avoid shutdown-inhibition caused by an interrupted, then completed, Ubuntu upgrade?

When I try to suspend/reboot my Ubuntu 18.04, I get a dialog asking for a password: "Authentication is required for suspending [respectively: rebooting] the system while an application asked to ...
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0answers
391 views

Ubuntu 18.04 (Gnome) authentication error when logging after lock/suspend

I have an issue with screen unlocking. It just rejects my password. And I noticed, it depends on time how long it was locked/suspended! If I unlock 10-20 min. after locking it accepts password and ...
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1answer
69 views

Why is 'Authenticated' setup of FTP on ubuntu very insecure?

I am reading the documentation for setting up an FTP server on Ubuntu, and the documentation states that using Authenticated users is very insecure. I dont understand why, because I am under the ...
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0answers
28 views

setting up pam stack with pam_google_authenticator - the most secure way

I've just tried to setup multi factor authentication for sshd, login, su, sudo, policykit, screensaver and lightdm. It works as expected and 2 factors are required to authenticate. ( plus public key ...
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0answers
76 views

Using Corporate Windows Authenticaion

We use a corporate Kerberos\LDAP authentication server that I would like to access in order to use that for authentication on a new Ubuntu 18.04 server. I know there is a way but I don't seem to be ...
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1answer
48 views

ssh authentication server does not work

i recently wanted to use ssh-keys instead of passwords for my server (Debian stretch). I am using an ubuntu subsystem on Windows (in case it matters). I was following the top answer from this thread: ...
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122 views

Can't login, “Authentication Error” after trying to login after system locks, fresh Ubuntu 18.04

After my desktop locks for the first time after my original login, I cannot unlock it again, it says "Authentication Error" even though I am positive I have typed my password correctly. It happens ...
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314 views

18.04 cached LDAP passwords

Over the last week I have been working on getting the (Ubuntu 18.04) LDAP directory information cached locally to allow the use of roaming users(on Laptops). Getting the LDAP client setup correctly ...
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167 views

Gnome-calender Authentication Request [duplicate]

In The Above ScreenShot there is some pop-up thats i will get when open some application. please kindly solve my problem how to close its permanently. I am Using 18.04 LTS How to trun its close ...
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0answers
19 views

Use CUPS with Chip Print Authentication

I have a Raspberry with CUPS installed. Before printing a print job, I want the user to authenticate via a chip directly on the Raspberry via the built-in chip reader before printing. I have not found ...
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0answers
39 views

Ubuntu Software Center will not allow installation of applications

I'm attempting to install PlayOnLinux, and every time I do, I get the error: Software can't be installed or removed because the authentication service is not available. (org.freedesktop.PolicyKit....
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0answers
450 views

How to install PAM for OpenVPN server?

I followed a guide on installing an OpenVPN server on Ubuntu successfully, and all is well with authenticating and connecting, etc. However, now I want to implement username/password authentication (...
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0answers
66 views

No Kerberos Auth wizard after installing krb5-user

I'm using Ubuntu 16.04 and am attempting to setup Kerberos authentication. Throughout the net every guide I came across shows this Wizard showing up right after installing this package. However, in my ...
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1answer
2k views

Can't ssh with key after upgrade/new install of 18.04 server

I have Ubuntu 18.04 on both desktop and server. Trying to login as user (not root) to server with ssh fails with "Permission denied (publickey)". SSH worked before with server being 16.04, but not now ...
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0answers
297 views

Ubuntu 18.04 fails to authenticate after first attempt

If I mistakenly type my password incorrectly, then Ubuntu shows message to say unable to authenticate, and then even if I enter correct password, it just shows a blank purple screen and doesn't take ...
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0answers
50 views

How to allow ssh authentication with public key and password

I have LDAP client on the running Ubuntu EC2 instance. Is it possible to make password-based authentication for LDAP users and Key based authentication for Ubuntu user?
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1answer
44 views

how do you required a user to login using key authentication?

I have created a new user and have generated them an rsa key on my local machine and manage to copy the public key content into that user ssh/authorized_key dir in the server. But somehow that user ...
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0answers
378 views

login loop Ubuntu 18.04 Radeon HD 7480D

I have an authentication problem on Ubuntu a kind of login loop on my session but not on the other session installed there (so I can do some things from this session, including changing password but ...
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1answer
606 views

SSH with Kerberos authentication

I am encountering the following problem: I am trying to connect from a client VM to a server VM using SSH with Kerberos authentication, but SSH still asking me for password. Obviously, I modified the /...
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1answer
231 views

Ubuntu 18.04 does not recognize users after bios (UEFI) update

I have updated from 17.10 to 18.04 successfully. I flashed my BIOS to a newer version. Now, when I go to enter my password, I am not recognized. Can this be fixed? ASUS TP300LD laptop i5 processor, ...
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1answer
833 views

Postfix authentication failure, can't send email out

I was trying to set up my postfix email server and got the following errors when using the command "auth login" in the telnet session with my postfix service: 535 5.7.8 Error: authentication failed: ...
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0answers
93 views

Where does pam get credential information?

I am learning how to write a application program which use pam to do authentication. I checked the Linux documents and some example codes, now I have a basic understanding about the pam APIs and pam ...
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2answers
138 views

sshd login get Permission denied (publickey). what am i doing wrong? [duplicate]

I am trying to login to an Ubuntu server from another Ubuntu machine via key. What I did on client: ssh-keygen -t rsa # generate ssh key And on the server /etc/ssh/sshd_config: # Package generated ...
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0answers
3k views

Permission denied (publickey) Amazon Linux aws

I have two instances running on my aws. I have the same keypair for both of them. I was using both instances for long time. but today I am getting an error on one instance while trying to login ...