Use this tag for questions relating to authentication mechanism (i.e. proving to the system that you are you, using passwords, keycards etc.). In general don't use this and the security tag on the same question, unless it is about the security of the authentication process.

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3
votes
2answers
131 views

SSH when to use public key and password?

I think I understand the difference between Public Key authentication and Password. But how do I decide which one to use and which one is most secure in what situation? Can anybody give me some real ...
3
votes
5answers
662 views

How to allow authentication with `sudo` using an alternate password?

I have been given a long password by my company for my Ubuntu system. This password is cumbersome to enter when authenticating with sudo repeatedly. Can I authenticate with sudo using a password ...
3
votes
3answers
218 views

Is there way to stop random software packages from remotely transferring your files?

I am running a bitcoin client on my archlinux computer. If somebody can get ahold of the wallet.dat file, located in the ~/.bitcoin/ directory they can steal my coins. I have minimal software ...
3
votes
2answers
9k views

su - user doesn't work for users without a password

I've created a user on CentOS with useradd -M username. Now, I want to become that user just like su - username. It asks me for a password for that user but I didn't set a password for that user. As ...
3
votes
2answers
522 views

How do you automatically elevate an automatic task to root privileges or is there an alternative approach?

I'm trying to write, in essence, an automatic deployment script for use by our development team and I know I can set up SSH to use keys so that I can automatically authenticate via key instead of ...
3
votes
1answer
43 views

Disabling ssh password authentication does not work on my debian VPS

I have a Debian 7 VPS setup. I just enabled SSH Key authentication and disabled password authentication but the disabling did not work. When I attempt to SSH into my VPS, it prompts me for my SSH Key ...
3
votes
1answer
5k views

Can't login as root even after resetting the password

We're running a small Centos 5 server in a virtual machine for a class assignment. For reasons unknown, starting about a week ago a number of services started failing. When we tried to investigate we ...
3
votes
1answer
16k views

How to enable remote login?

Currently I can only login to my remote linux via the "ubuntu" user account, without a password (via SSH authentication). I have another user configured on the machine, and if I try to login with its ...
3
votes
2answers
65 views

Why user without any PASSWD entry in sudo config has to authenticate every time?

Consider this sudo config for two users: mary ALL = (ALL) NOPASSWD: /bin/ls, /bin/cat bob ALL = (ALL) PASSWD: /bin/sort Now, when user mary executes any command not in the list she has to ...
3
votes
1answer
2k views

mod_authnz_ldap bind as authenticating user instead of anonymously

I'm attempting to move as close to single credential as possible. We have a web application that has a fairly limited set of available authentication mechanisms but will (luckily) allow admins to tell ...
3
votes
2answers
831 views

Where does Samba 4 store user passwords?

Where does Samba 4 store user passwords? How can I import my password hashes from Samba 3 in Samba 4? I am using my own LDAP server with samba 3, and the password hash is stored within the ...
3
votes
1answer
197 views

How are loaded SSH keys referenced by name?

I'm using chef's knife ec2 tool which requires the name of a loaded SSH key (that was created in the Amazon EC2 control panel) It seems strange to me that it uses a name to reference the keypair - ...
3
votes
2answers
45 views

How to stop sudo PAM messages in auth.log for a specific user?

I am using Zabbix for monitoring my environment and zabbix_agentd executes as user zabbix one custom script every 60 seconds; it uses sudo to run this script as root. In /var/log/auth.log I see every ...
3
votes
1answer
73 views

Use ssh without trying ssh-keys

If I try to connect to a certain server with ssh example.com ssh aborts with Too many authentication failures because I have more than 5 ssh keys in my .ssh folder and it loops through all those ...
3
votes
1answer
873 views

How to set an expired authentication in Apache?

Using a simple virtual host, I've to set a timeout after X minutes (same of set an expired authentication) to force the user to re-insert its credentials. [...] <Directory /home/user1/> ...
3
votes
1answer
1k views

Firefox error message when adding client certificate signed by CA

I'm getting this message when I'm trying to add a certificate to Firefox's "your certificate tab". I generated and signed it before by a server which also is a CA. Failed to decode the file. ...
3
votes
1answer
433 views

Invoking PolicyKit/polkit via xinit/startx?

I recently upgraded a minimal installation of Ubuntu (with no full-fledged DE) from precise to saucy and since doing so I'm no longer able to mount removable drives as a normal user. I googled a bit ...
3
votes
1answer
581 views

Multiple PCs network centralized system authentication

(I couldn't really choose an accurate title as I don't know exactly what the feature I'm looking for is called. Sorry about that. I hope that the following lines may clear this aspect.) I own a dozen ...
3
votes
1answer
4k views

Where to supply authentication details to the Network Proxy (Central Proxy) on Fedora?

My system is running Fedora 16 and I live in a campus where we use LAN to connect to the Internet. And for this, we use an http proxy with authentication (username & password). I tried putting the ...
3
votes
1answer
561 views

What's the best way to install a system-wide certificate from a website?

I want to use the Cisco Easy VPN to connect to the OpSource cloud machines. When I open the app, it directly shows a certificate error message, I suspect that the certificate is not trusted from their ...
3
votes
0answers
91 views

Why is my SSH authentication socket different from the man pages?

These two entries of man ssh-agent describe the SSH authentication socket: $TMPDIR/ssh-XXXXXXXXXX/agent.<ppid> UNIX-domain sockets used to contain the connection to the authentication ...
3
votes
0answers
2k views

Setup LDAP client on RHEL 6.5

I am preparing for RHCSA exams and trying to setup LDAP client on my RHEL 6.5 box I am connecting to the online testing LDAP server Here I don't understand the relationship among following 3 files, ...
3
votes
1answer
465 views

recover email from imap account using mailx

I am having problems fetching emails with mailx. My imap account uses ssl/tls connection with normal password authentication on port 993. I don't have any problems sending through smtp though. Here is ...
3
votes
0answers
171 views

WGET - Authenticating root AND all children folders

Before I start the question off, I want to say that a similar question helped me get past the initial login. My issue is as stated below. There's a website that I'm trying to mirror. It is something ...
3
votes
1answer
399 views

Configure applications to ask for a user:pass behind a proxy

Here's the deal: I'm trying to set up a SQL server with Debian Linux, I managed to install Debian - but I can't get apt-get to work, since I'm behind a proxy. I already managed to setup Iceweasel to ...
2
votes
3answers
222 views

Can sudo replace su?

There is much duplication of functionality on Linux-based systems, for example these do the same thing: sudo --login --user <user> sudo su - <user> The sudo-only approach looks more ...
2
votes
2answers
2k views

How to get hashed password in /etc/shadow using getpwnam()?

Apparently there is a function (getpwnam) that given a username, will return the appropriate entry in /etc/passwd with the other details for that user (shell, uid, gid, etc.). However, I have no idea ...
2
votes
2answers
838 views

ssh login in Bash script

I've been working on a series of scripts to perform tasks on my remote server, but have gotten stuck at how to log in via ssh mid script, as I cannot enter the password automatically. Is there a way ...
2
votes
5answers
188 views

Simulate the remote host identification warning

I need to simulate the warning: @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING ...
2
votes
2answers
66 views

Add a user wthout password but with SSH and public key

I want to add a user to Red Hat Linux that will not use a password for logging in, but instead use a public key for ssh. This would be on the command line.
2
votes
2answers
1k views

How to sign into an open Wireless Network?

I'm running Arch Linux on my netbook. My school have an open Access Point and we must sign into the network via a page which we are redirected to when we try to open whatever website if we are not ...
2
votes
1answer
2k views

Script to get file from SFTP and run it

We have 5 servers running our code: A, B , C, D and E. From a local machine, we sftp the file to A. Then ssh id@A su - applicationname sftp id@A get <file> bye tar -xzf <file> logout ...
2
votes
2answers
183 views

temporarily disable login using one specific ssh key

On my server, I have several public SSH keys in ~/.ssh/authorized_keys. I would like to temporarily block/disallow/deactivate one key. I want to prevent the user to log in using this key now. but I ...
2
votes
1answer
712 views

How do I reset RHEL6 to autocreate home directory upon login?

I am using a RHEL6 host that is set up using LDAP for authenication. Upon first login it is supposed to create the home directory for the user (e.g. /home/gisle where gisle is my login username). I ...
2
votes
2answers
383 views

How do I switch from /etc/shadow back to /etc/passwd?

I'm playing with a rather old, heavily customized Linux installation (based on Debian etch, running on a Netgear ReadyNAS device). Recently I've switched from /etc/passwd to /etc/shadow via pwconv. ...
2
votes
1answer
7k views

How to setup proxy authentication in the Debian shell?

I think that once I used export http_proxy=http://user:password@address:port/ successfully. But now when I use wget it shows Error parsing proxy URL http://user:passwordaddress:port/: Bad port ...
2
votes
2answers
1k views

setting up ssh public key

Okay, so I'm trying to setup a login for logging in with ssh, using a public key. First, I am using puttygen to generate a rsa-ssh2 public key using a passphrase. I followed the directions and ...
2
votes
1answer
61 views

n-factor SSH authentication for CentOS 7

How can I enable (and require) n-factor authentication for all SSH connections to a CentOS 7 server? I have read about Google Authenticator, which provides two factor authentication. But that is ...
2
votes
1answer
188 views

Locally deny login to users authenticated via LDAP

I have a RedHat Linux server that are is use for more than 1000 users Users names are coming to the server via LDAP protocol, so login authentication is from the LDAP My question: is it possible to ...
2
votes
1answer
161 views

What's the correct way to authenticate a user without PAM?

as my related question doesn't seem to get much love, here another one: What's the proper way to authenticate a user via username/password prompt in Linux nowadays? In principle, I suppose I would ...
2
votes
1answer
147 views

Apache authentication mutiple domain but same subdirectory

I've got several sites: example.com, example1.com, and example2.com in my wordpress. All of them point to my server's /public_html folder, which is my Apache root folder. What do I need to add to my ...
2
votes
2answers
126 views

Making su ask for password multiple times

Is there some way to make su ask for the password again in case of a wrong password (just as sudo does)? Initially I thought of this: while ! su -c foo; do read -n 1 -p "Retry(y/n)?" ch if [[ ...
2
votes
1answer
2k views

PPTP VPN error: LCP terminated by peer

I cannot connect to my PPTP VPN server, even though the CHAP authentication succeeds. This is from /var/log/syslog: Jun 11 07:27:22 aspire pppd[32221]: CHAP authentication succeeded Jun 11 07:27:22 ...
2
votes
1answer
391 views

login 'authentication failure' by non-root user, can login only by root [closed]

In my CentOS 6.0 system, working since months, suddenly stop authenticating non-root users, in graphical mode. I have checked necessary /etc/pam.d/* files, but those are unchanged. SELinux is ...
2
votes
1answer
621 views

Gnome-shell authentication dialogue fails, how to debug which app is using it?

I am using ubuntu 13.10 with gnome shell 3.8.4. I used to use gnome online accounts for empathy and other things, but then I stopped using them. And then gnome shell started to show authentication ...
2
votes
1answer
2k views

tinyproxy with user authentification

Does anybody have a solution that'll make tinyproxy work with user authentification like pam_auth at the squid proxy? I don't want to create a SSH-Tunnel and allow only localhost.
2
votes
1answer
4k views

Authenticating with x11vnc: what's the difference between -auth and -rfbauth?

I'm on xubuntu 11.10 trying to setup x11vnc server. I followed instructions here and I can connect to VNC server - but it never asks me for password! Is there a difference between these 2 options: ...
2
votes
2answers
1k views

SSH on my local network - problem with login

I'm having problem with logging into my local-network-linux (server) ssh with Putty (and with Linux terminal, too) When my server shows me request to insert username, I insert "root" and I do press ...
2
votes
1answer
48 views

Configure OpenSSH server not to require password *or* key for a particular user

For the purpose of a training session, I'd like to make it possible for a particular user to connect without requiring a password or key-based authentication. I do not know the IPs or other data of ...
2
votes
1answer
34 views

Directory Server doing lookups on one ldap server and authintication on another ldap server

I have an old Centos Directory Server and a new 389 Directory Server. I don't want to use sssd at the moment so lets keep that suggestion off the table. I do the following my RHEL 6.4 servers: ...