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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61
votes
3answers
16k views

Why is there a big delay after entering a wrong password?

I notice a weird (well, according to me) thing about passwords. For example, if I type an incorrect password during login, there will be a few seconds' delay before the system tells me so. When I try ...
1
vote
1answer
2k views

Failed to sign CSR with the CA root key

I'm trying to implement Mutual Certificate Authentication , I have to be the CA and server at the same time , generate certificates and sign them for users. and I'm following this tutorial which is a ...
7
votes
3answers
643 views

login and su internals

I am trying to understand how user permissions work in Linux. The kernel boots and starts init as root, right? Init then runs startup scripts and runs getty (agetty), again as root. Agetty just reads ...
7
votes
2answers
5k views

How can I set up SSH on Linux to log in password-less?

My Raspberry Pi is running the default Debian image and has SSH enabled. I log into my Pi as follows: ssh pi@<IP-address-of-my-Pi> I have to enter my password every time. Can I somehow make ...
35
votes
7answers
20k views

Can I find out which ssh key was used to access an account?

Is it possible to find out which ssh key was used to access an account? I have an account on a server that I let several (trusted!) people have access to via ssh. I'd find it useful to be able to ...
13
votes
3answers
41k views

I Can't login as root with su command, but I can with SSH

How is it possible that I cannot log in as root by su root or su (I get incorrect password error), but I can log in by ssh root@localhost or ssh root@my_local_IP with the same password? I'm using ...
13
votes
3answers
25k views

ssh remote server on some port other than 22 without password

I am usually connecting to the remote server with ssh user@server.com -p 11000 and then giving the password each time for user. How should I avoid entering the password each time I connect ...
10
votes
1answer
2k views

D-Bus authentication and authorization

I'm trying to set up remote access to D-Bus, and I don't understand how authentication and authorization are (not) working. I have a D-Bus server listening on an abstract socket. $ echo $...
9
votes
2answers
11k views

Not able to ssh in to remote machine using shell script in Crontab

Below is the script which i am trying to run, which runs without any issue for i in `seq 200 2100` do usr=(`ssh -t -t -o ConnectTimeout=60 machine$1 finger | tail -1 | awk '{print$1}'`) echo $...
6
votes
5answers
28k views

vsftpd fails pam authentication

Moving a tried-and-true vsftpd configuration onto a new server with Fedora 16, I ran into a problem. All seems to go as it should, but user authentication fails. I cannot find any entry in any log ...
2
votes
1answer
9k 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 ...
15
votes
3answers
21k views

Allow user1 to “su - user2” without password

I need to allow user martin to switch to user martin-test without password su - martin-test I think this can be configured in /etc/pam.d/su. There are already some lines in that file which can be ...
26
votes
3answers
31k views

Permit root to login via ssh only with key-based authentication

I have some doubts about certain ssh server configurations on /etc/ssh/sshd_config. I want the next behavior: Public key authentication is the only way to authenticate as root (no password ...
19
votes
5answers
9k views

Gmail blocking mutt

When I try to log in to gmail with mutt, it flashes a quick Webalert with a url, something like accounts.gmail.com or something. It's too quick for me to see or copy it. Then it says Login failed. ...
4
votes
3answers
9k views

CentOS use .pac file as proxy

I have to use a proxy with authentication to connect to the Internet. But I can't find any solution for this. I have modify my yum.conf, with a lot of possibilities: proxy=http://myproxy.domaine.com:...
11
votes
2answers
30k views

How to telnet via proxy authentication?

I am behind a proxy server in my college. It uses a simple username and password authentication. And i connect to the proxy server to port 3128. now i want to telnet simply to say any website on the ...
9
votes
1answer
2k views

SSH keeps skipping my pubkey and asking for a password

Everytime I ssh onto my remote server I need to provide the password. I copied my public key (id_dsa.pub) to the remote server using: ssh-copy-id -i id_dsa.pub user@server I checked it was ...
5
votes
3answers
11k views

Authentication refused: bad ownership or modes for file /var/git/.ssh/authorized_keys [duplicate]

EDIT The issue as exposed here is solved (about files modes of the .ssh folder. But an other issue persists so I create a new question : > Unable to login with SSH-RSA key I can no longer ...
2
votes
2answers
3k 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 ...
7
votes
2answers
487 views

iPhone type login screen?

The person that introduced me to Fedora had somehow made his login screen so that instead of typing in a password he used the "connect the dots" password that's popular on phones. Eg On my ...
4
votes
1answer
780 views

Configuring Apache to Require a Client Certificate

I want to implement mutual authentication (two - way ) with apache web server. References : 1.Failed to sign CSR with the CA root key 2.Firefox error message when adding client certificate ...
4
votes
1answer
1k views

Program to keep track number of login attempts

Is there any way to keep track of number of attempts made by a user to login into his system?
3
votes
1answer
2k 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
0answers
445 views

SSL Configurations for Intermediate certificate

I had implement a mutual certificate authentication and it worked successfully for following steps : create root ca (self-signed) create server certificate and sign it with ca private key create ...
3
votes
3answers
226 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 ...
2
votes
1answer
435 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
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
5answers
317 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
1k views

How to send mail from a remote SMTP host?

I have Postfix suite installed locally on Ubuntu 10.10. I can send/receive mail to my local address, e.g. user@local.com. I'm given credentials to a remote mail server mailbox, e.g. other@remote.com....
1
vote
1answer
2k views

Cannot login for one user, changing password have no effect

I have change the user's (user1) password using root passwd user1 but when i tried to ssh user@localhost or through gdm or tty it always failed the journalctl log shows Failed password for user1 ...
1
vote
2answers
681 views

Unable to login with SSH-RSA key

This post is following this question : Authentication refused: bad ownership or modes for file /var/git/.ssh/authorized_keys . The issue as exposed there is solved (about files modes of the ....