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Questions tagged [authentication]

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

4
votes
1answer
226 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 ...
1
vote
0answers
29 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 ...
1
vote
0answers
30 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 ...
0
votes
1answer
90 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 ...
0
votes
1answer
26 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 ...
1
vote
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 ...
0
votes
0answers
25 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 ...
2
votes
2answers
125 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 ...
2
votes
1answer
37 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 ...
0
votes
0answers
29 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 ...
0
votes
0answers
27 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. ...
1
vote
1answer
272 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.
0
votes
1answer
41 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 ...
1
vote
0answers
60 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 ...
0
votes
1answer
51 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 ...
1
vote
1answer
39 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 ...
0
votes
0answers
38 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 ...
0
votes
0answers
166 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 ...
2
votes
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 ...
0
votes
0answers
22 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 ...
0
votes
0answers
75 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 ...
0
votes
1answer
47 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: ...
0
votes
0answers
92 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 ...
1
vote
0answers
164 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 ...
0
votes
0answers
41 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 ...
0
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0answers
16 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 ...
0
votes
0answers
38 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....
0
votes
0answers
230 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 (...
0
votes
0answers
30 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 ...
0
votes
1answer
1k 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 ...
1
vote
0answers
208 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 ...
0
votes
0answers
46 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?
0
votes
1answer
42 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 ...
0
votes
0answers
342 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 ...
1
vote
1answer
257 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 /...
1
vote
1answer
225 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, ...
1
vote
1answer
380 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: ...
0
votes
0answers
56 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 ...
3
votes
2answers
122 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 ...
3
votes
0answers
2k 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 ...
1
vote
0answers
13 views

A little question on reverse proxies via mod_proxy on 16.04

I've run into a little bit of a hump and would like a bit of feedback from the community as I'm not sure how best to proceed. I have created a reverse proxy that allows the user to login into a ...
5
votes
0answers
600 views

Why does my laptop say “Authentication failure” when resuming after suspending?

I have Ubuntu 16.04LTS on my laptop and, up until the last batch of updates were installed when, I suspended by closing the lid it would simply prompt me to enter my password when I resumed by opening ...
0
votes
0answers
62 views

How to change password encoding to blowfish for nis client using auth-client-config at ubuntu 18.04

installation of pam-unix2 result: /etc/pam.d/common-password password [success=2 default=ignore] pam_unix2.so obscure blowfish password sufficient pam_sss.so ...
2
votes
0answers
46 views

Connect Ubuntu 16.04 Desktop to LDAP Server [duplicate]

I use Ubuntu 16.04 LTS desktopand read and tested a lot of documentation about configuring an LDAP client on Ubuntu but can't get it to work. Is someone can share his experience and give me some good ...
1
vote
0answers
309 views

Ubuntu Server 16.04 Squid Proxy authentication with 2 NIC setup

I have an ubuntu proxy running server 16.04, squid 3.5.12 and NCSA. The server has two NICs, one connected to internet router, eno1 with IP 192.168.1.2/24 and another connected to client LAN, eno2 ...
1
vote
1answer
395 views

How to set up centralized user authentication on Ubuntu?

I have installed OpenLDAP, and configured some basic users. Next, I want to configure users in my directory to be able to authenticate through my server. I was reading a little about something called ...
1
vote
1answer
775 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 ...
0
votes
0answers
17 views

I can't create users with ldap

I've installed ldap-utils, slapd, libpam-ldap, libnss-ldap, nscd, nslcd, libpam-mount and phpldapadmin on my server. And ldap-utils, libpam-ldap, libnss-ldap, nscd, nslcd on the client. I configured ...
0
votes
0answers
36 views

PAM-PGSQL authentication succeeds but user cannot access the file system

Synopsis: I would like to use PostgreSQL as the authentication server for my Linux users via PAM. For this purpose, I use the libnss-pgsql2 library. The Linux distro is Ubuntu 14.04. So far, I have ...
0
votes
1answer
131 views

Can't run synaptic on an xfce ubuntu system

So I installed Ubuntu with xfce (using crouton) and tried to run synaptic and ran into the following: $ synaptic-pkexec ==== AUTHENTICATING FOR com.ubuntu.pkexec.synaptic === Authentication is ...