Secure Shell (SSH) is a protocol primarily for encrypted shell connections. This tag is also used for questions about sshd and openssh, the two standard applications for using SSH.

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23
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1answer
5k views

Why does my OpenSSH key fingerprint not match the AWS EC2 console keypair fingerprint?

When I import my OpenSSH public key into AWS EC2's keyring the fingerprint that AWS shows doesn't match what I see from: ssh-keygen -l -f my_key It is a different length and has different bytes. ...
24
votes
2answers
34k views

public key authentication fails ONLY when sshd is daemon

I have no clue on how this happens. The distro is Scientific Linux 6.1 and everything is set up to perform authentication via public key. Yet, when sshd is running as a daemon (service sshd start), it ...
33
votes
9answers
35k views

How can I automatically change directory on ssh login?

I'm trying to get ssh to automatically change to a particular directory when I log in. I tried to get that behaviour working using the following directives in ~/.ssh/config: Host example.net ...
9
votes
3answers
5k views

Trying to get SSH with public key (no password) + google authenticator working on Ubuntu 14.04.1

I'm using Ubuntu 14.04.1 (with OpenSSH 6.6 and libpam-google-authenticator 20130529-2). I'm trying to set up SSH logins where the public key authenticates (without a password) and a user is prompted ...
9
votes
3answers
12k views

How can I use the same key for SSH and SSL (https)

I'm trying to install the development tools for a small team, and I can't get the authentication right. Since we are a distributed team, the server is on the internet. And I'd like to have SSO+zero ...
30
votes
7answers
6k views

SSH: Two Factor Authentication

I currently have a Ubuntu Server 12.04 running OpenSSH along with Samba and a few other services. At the current time I have public key authentication set up, and I'm wondering if it's possible to set ...
21
votes
6answers
7k views

Can I use PLink and Pageant with Cygwin's ssh?

I'm now using msysgit because of the GUI tools, which use Putty's Pageant and PLink utilities, but I use Cygwin as a general SSH terminal. I had been using ssh-agent on Cygwin, but that means I have ...
16
votes
2answers
29k views

How to check if a RSA public / private key pair matched

I have two files, id_rsa and id_rsa.pub, what command can be used to validate if they are the valid pair.
11
votes
10answers
18k views

DNS Name lookup (was SSH) Not Working After Snow Leopard Upgrade

I think this started with the Snow Leopard update. Cleaned out the .ssh directory, still having the issue. ~: uname -a Darwin california-example-com.local 10.0.0 Darwin Kernel Version 10.0.0: Fri ...
20
votes
4answers
7k views

How to handle SSH port changes with Ansible?

I'm trying to use Ansible for automating the setup process of new server instances. One of the setup tasks changes the default SSH port, therefore requiring me to update the hosts list. Is it ...
20
votes
6answers
15k views

How can I set proxy for subversion with ssh tunnel?

I want to check out/update the code via proxy since my local connection is slow. I setup ssh tunnel : ssh -D 8090 user@ssh.proxy.net to forward all the packets to my localhost:8090. How can I set up ...
10
votes
4answers
3k views

SCP filename tab completion

I use SCP regularly to move files between servers and I've heard rumoured that you can use tab-completion on the remote server if you're using public keys, but so far I have had no luck. What I'm ...
18
votes
5answers
11k views

SSH: Do you use one private/public key pair for each remote machine? Or a single pair for all?

When you want to have public key based ssh logins for multiple machines, do you use one private key, and put the same public key on all of the machines? Or do you have one private/public key pair for ...
10
votes
4answers
6k views

When would ssh -t not be appropriate instead of ssh?

Using ssh -t instead of ssh for connections to remote servers has several advantages. For example, I can directly edit a file with vim: ssh -t host vim foo.txt, which would fail otherwise. Are there ...
20
votes
7answers
6k views

Restart SSH on a machine where SSH is the only mode of access

I've made some changes to sshd_config file and therefore need to restart. I'm looking tips on safely restarting ssh when getting physical access to the server would be a huga PITA.
19
votes
7answers
5k views

I screwed up, exit in .bashrc

I put "exit" in my .bashrc file. I don't have physical access to the machine so to connect to it I use ssh. I don't have root privileges. Every time I connect to the server, the connection ...
14
votes
4answers
69k views

Free public SSH server for testing purposes [closed]

I'm writing an application that makes connections to SSH servers. It doesn't need anything specific from the server (except running under GNU/Linux). I need SSH servers for running my application ...
13
votes
3answers
8k views

Set up sftp to use password but ssh not to use password

Is it possible to set up a user on ubuntu with openssh so that ssh does not use password authentication but sftp does? I assume that if I change /etc/ssh/ssh_config to have PasswordAuthentication yes ...
10
votes
2answers
11k views

SSH Connections freezing with “Write failed: Broken pipe”

I am connecting to a CentOS 5.5 box via SSH from a Ubuntu 11.04 machine. The connection appears to work as expected when it is in active use (i.e. no lag or loss), but if it is left inactive for a ...
10
votes
2answers
6k views

How can I close SSH tunnel gracefully?

I have open tunnel with ssh -2 -N -L 5001:localhost:1019 eonil@test.local The tunnel is working good, but I have to Ctrl+C or Ctrl+D to force quit the tunnel. How can I close the tunnel gracefully? ...
10
votes
5answers
10k views

Can I create SSH to tunnel HTTP through server like it was proxy?

Say I have a server and client. I need to create connection from client to a website through server like it was proxy. Is it possible to do this using a SSH tunel, or do I have to install some proxy ...
5
votes
2answers
2k views

Easy multi-level authentication for sudo

I have a FreeBSD server with password-based SSH enabled. I would like to enable sudo, but I do not want a potential attacker to be one password away from root access. My current solution is logging ...
3
votes
11answers
862 views

Ubuntu Server SSH

I have a server with ubuntu. I do work on it over SSH. I had a problem with brute force attempts over port 22. I changed the port and I assumed it fixed the brute force problem. Am I right or are the ...
16
votes
3answers
17k views

What options can be put into a SSH authorized_keys file?

I found this article on options that can be put before a key in the authorized_keys file. I was wondering though, are there more? Options listed in the article are from="domain" ...
14
votes
13answers
37k views

Stop ssh login from printing motd from the client?

I've got SSH passwordless set up, however it prints the MoTD when it logs in. Is there anyway to stop that happening from the client side? I've tried ssh -q but that doesn't work. I don't want to use ...
13
votes
3answers
2k views

Inline SSH command

Is it possible to do a simple inline style SSH command, for example: ssh foo@bar.com { cd foo/bar && rm *.foobar }
13
votes
4answers
6k views

Using PGP keys for SSH

I use a 4096 byte RSA PGP key; since SSH also uses the RSA standard, is it at all possible to use the PGP key as an SSH key without installing additional software on the server (and as little as ...
10
votes
2answers
2k views

SSH MOTD per user

I want to display banner (welcome message) for SSH users with a specific welcome message for each user.
10
votes
4answers
26k views

SSH X11 not working

I have a home and work computer, the home computer has a static IP address. If I ssh from my work computer to my home computer, the ssh connection works but X11 applications are not displayed. In my ...
9
votes
2answers
25k views

bad ownership or modes for chroot directory component

I created the user MY_USER. Set his home dir to /var/www/RESTRICTED_DIR, which is the path he should be restricted to. Then I edited sshd_config and set: Match user MY_USER ChrootDirectory ...
9
votes
5answers
9k views

How can I automatically change terminal colors when I ssh a server?

I'm frequently logging into different servers from my os x terminal window. I'd like to assign a color scheme for different hosts so that my terminal windows are easier to tell apart. Can this be ...
8
votes
5answers
4k views

Stop ssh client from offering all the public keys it can find?

Like most sysadmins I use openssh all the time. I have about a dozen ssh keys, I like to have a different ssh key for each host. However this causes a problem when I am connecting to a host for the ...
8
votes
4answers
7k views

Transfer files via SSH

I want to use file transfer via SSH on some scripts. I've read it's possible to tar over ssh. Where should I start reading?
6
votes
1answer
1k views

Adding port forwardings programmatically on a ControlMaster SSH session

I just found out about the ControlMaster/ControlPath feature of OpenSSH, which allows you to use a single SSH connection to run multiple terminals. As I often use SSH to use port forwarding to get ...
5
votes
5answers
6k views

How can I disconnect ssh users, or limit the number of ssh logins?

I have an application that is using ssh to authenticate. Due to a variety of regulations (HIPAA, etc) users can only be logged in for a certain amount of time, and they can only be logged in once. I ...
5
votes
8answers
21k views

Is it possible to prevent SCP while still allowing SSH access?

Using Solaris and Linux servers and OpenSSH, is it possible to prevent users from copying files using "scp" while still allowing shell access with "ssh"? I realize that 'ssh $server "cat file" ' type ...
4
votes
3answers
9k views

How can I enable X11 forwarding to a Debian server box?

I want to connect to a server with SSH (a Debian installation in a VMware image). On that server I want to call gitk a repository viewer for git. What do I need to do to make this work?
1
vote
2answers
4k views

ssh remote command-fu

I am trying to do a remote backup from behind a firewall. It is really no problem to break this out into its own script that gets called in crontab, but that isn't any fun! What I am trying to do ...
19
votes
5answers
22k views

Ssh, run a command on login, and then Stay Logged In?

I tried this with expect, but it didn't work: it closed the connection at the end. Can we run a script via ssh which will log into remote machines, run a command, and not disconnect? So ssh in a ...
18
votes
4answers
11k views

What is the benefit of not allocating a terminal in ssh?

Every once in a while I will do something like ssh user@host sudo thing and I am reminded that ssh doesn't allocate a pseudo-tty by default. Why doesn't it? What benefits would I be losing if I ...
17
votes
1answer
5k views

Is it possible to run sshd as a normal user?

I'm aiming to start up a second sshd instance on a non-privileged port (e.g. 2222) with my own configuration file. Obviously, the sshd process can't setuid so logging in as users other than the one ...
15
votes
5answers
18k views

Force SSH to use a specific shell

Is there any way to force SSH to use a particular shell on the remote end, regardless of what the user's default shell is? I've tried solutions akin to: ssh host.domain.com /bin/bash -c ...
12
votes
11answers
12k views

Best way to go about changing a root password on 3000+ Solaris, AIX, and Linux servers?

Long story short: Big old corporation, lots of UNIX/Linux servers. I inherited responsibility for a bunch of scripts that that left a few years ago. One of them was a script that would be run every ...
10
votes
1answer
3k views

Only allow password authentication to SSH server from internal network

I have an OpenSSH 5.9p1 server running on Ubuntu Precise 12.04 which accepts connections from both the internal network and the Internet. I'd like to require public key authentication for connections ...
10
votes
2answers
9k views

Authentication Order with SSH

When I login via ssh with -v I see that ssh is authenticating the following way debug1: Authentications that can continue: publickey,gssapi-with-mic,password,hostbased I would like to change the ...
9
votes
2answers
16k views

SFTP fatal bad ownership or modes for chroot directory ubuntu 12.04

I just set up my SFTP server and it works fine when I use it from my first user account. I wanted to add a user which we will call 'magnarp'. At first I did like this in sshd_config: Subsystem sftp ...
8
votes
3answers
3k views

Restricting the network access of Docker container

I'm in the process of creating an SFTP only Docker container, one that will be used by multiple people for the sole purpose of uploading and managing files in their own chrooted Environment. On ...
8
votes
2answers
13k views

SSH tunnel over multi hops using putty

I have a situation where I want to connect to a Linux machine running VNC (lets call it VNCServer) which is behind two consecutive Linux machines i.e., to ssh into the VNCServer, I have to ssh into ...
8
votes
3answers
3k views

OpenSSH with public keys from database

Is it possible to fetch the public keys from a database instead of the authorized_keys file? I would like to use such a setup to manage ssh access to things like git repositories for multiple users ...
8
votes
1answer
2k views

SSH passphrase remembered in MacOSX Snow Leopard

I am facing a very strange situation with Snow Leopard. I have a Linux server, configured to accept an ssh connection authenticated only through RSA key. No password. On my laptop I correctly deployed ...