SSH (Secure SHell) is a protocol for running commands on a remote computer.

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SSH key-based authentication: known_hosts vs authorized_keys

I read about setting up ssh keys in Linux and have some questions. Correct me if I'm wrong… Let's say host tr-lgto wants to connect to host tr-mdm using ssh. If we want to be sure that it's the real ...
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1answer
3k views

Reusing ssh session for repeated rsync commands [duplicate]

Possible Duplicate: Using an already established SSH channel I have a remote server accessible via a chain of SSH proxies. The resulting channel is wide and fast enough, but setting it up ...
13
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6answers
7k views

SSH automatic remote back ups

I have two machines, A and B. Machine A can ssh into B. A has a lot of free space. B's data is in a sort of risky situation. How do I back up all of B's data to A automatically. It does not have to ...
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3answers
6k views

How can I make a user able to log in with ssh keys but not with a password?

I would like to create a user and have no password. As in you cant log in with a password. I want to add keys to its authorized_keys by using root. This is for my automated backup system.
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2answers
11k views

How do I force a user to change a password at the first time login using ssh?

I'm trying to force a newly created user to change a password at the first time login using ssh. For security reasons I want to give him a secure password until he logs in for the first time. I did ...
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4answers
5k views

How can I set default settings for htop?

Occasionally, I need to check resources on several machines throughout our data-centers for consolidation recommendations and the like. I prefer htop, mostly because of the interactive feel and the ...
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4answers
66k views

Can I transfer files using SSH?

I am using PuTTY on Windows 7 to SSH to my school computer lab. Can I transfer files from my Windows machine to my user on the school machines using SSH?
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3answers
9k views

How to execute a remote command and pass in local file as input?

Is it possible to do this: ssh user@socket command /path/to/file/on/local/machine That is to say, I want to execute a remote command using a local file in one step, without first using scp to copy ...
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3answers
18k views

How can I track who SSH'es into my linux machine?

I'm running Ubuntu 10.04. Is there a way I can get a daily report of who has logged onto the box, what time, and even - this may be asking too much - a report of the commands they used? This is a ...
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3answers
3k views

Can SSH passwords be sniffed out over Wi-Fi?

When you ssh, can the password you enter to connect, be intercepted if you're using untrusted public Wi-Fi (coffee shop, library, airport, etc).
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4answers
950 views

Groups differ from the local ones when logging in remotely

We store our users in LDAP, alongside some groups that have meaning across different systems (organizational roles including wheel). There are also groups local to workstations, e.g. audio or video ...
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3answers
9k views

Run a diff between local and remote files

I'm connected on a host via ssh and I'd like to compare (let's say with diff) a certain config file against its counterpart on an another host, also accessible via ssh, without having to manually ...
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4answers
7k views

Given keys in ~/.ssh/authorized_keys format, can you determine key strength easily?

~/.ssh/authorized_keys[2] contains the list of public keys. Unfortunately, each public key does not specify the key strength ( number of bits ). Is there a utility that can process this file line by ...
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4answers
4k views

How can I keep my SSH sessions from freezing?

I have ServerAliveInterval and in case of few machines also ClientAliveInterval set to 540 in SSH client/server configuration files (I suppose setting it to more than that would not be a good idea). I ...
12
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5answers
22k views

Use socks proxy for commands in terminal

I connect to a remote ssh server by running this command: ssh -D 12345 bob@myserver.com This creates a socks proxy that I can use with Firefox to bypass censorship in my country. However, I can't ...
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4answers
3k views

Stopping output from a program run in SSH session NOW

Problem I execute command that outputs LOTS of information through SSH. For example, I foolishly add debug information inside a loop that executes million times, or just run cat /dev/urandom for ...
12
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4answers
3k views

Advice for managing SSH keys

What is the best practice you have found for managing lots of SSH keypairs? I use SSH to connect to several systems, both at home and at work. I currently have a fairly small, manageable collection ...
12
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3answers
20k views

Why does my X11 forwarding attempt fail with “connect /tmp/.X11-unix/X0: No such file or directory”?

On my local machine, I run: ssh -X me@remotemachine.com (For completeness, I have also tested all of the following using -Y with identical results). As expected, this accesses remotemachine.com ...
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2answers
38k views

How to add a ssh user who only has permissions to access specific folder?

How to add an ssh user who only has permissions to access specific folder? useradd -d /var/www/xyz.com.tr/musteri -s /bin/bash -g sshd musteri I created a user called musteri. I set its home ...
12
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1answer
793 views

How to execute an arbitrary simple command over ssh without knowing the login shell of the remote user?

ssh has an annoying feature in that when you run: ssh user@host cmd and "here's" "one arg" Instead of running that cmd with its arguments on host, it concatenates that cmd and arguments with spaces ...
12
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1answer
6k views

Tail log file on multiple machines over ssh

I'm trying to tail a log file on multiple remote machines and forward the output to my local workstation. I want connections to close when pressing Ctrl-C. At the moment I have the following function ...
12
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2answers
7k views

How to pipe a remote file to stdout over scp or sftp?

Using ssh, it is easy to print the contents of a file using ssh host 'cat file.txt' When ssh is disabled, and only SFTP is enabled, running the previous command gives the following error: ...
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2answers
37k views

Server does not accept public key for ssh login without password [duplicate]

Possible Duplicate: Why am I still getting a password prompt with ssh with public key authentication? I have ssh access to two sever. One old one and one new one. For the old one I use the ...
12
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3answers
2k views

Adding a user who can only execute scripts remotely

I would like to create a user who can only do one thing: via ssh specify a script ( and commandline arguments to the script ) that resides in one particular folder ( for the purposes of this question ...
12
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2answers
25k views

How to edit authorized_keys?

What is the best method for editing the /root/.ssh/authorized_keys file? I mean if I need to append a new key to my authorized_keys file, than what are the best methods to do that?
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1answer
14k views

Foreign characters won't display in SSH

I'm having some problems with using ssh and a remote server (which I do not have admin access to) - Specifically, there are a couple of folders on there with Korean and Cyrillic text. When I display ...
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2answers
24k views

Meaning of “Connection closed by xxx [preauth]” in sshd logs

We have a Windows batch script, which connects automatically to a linux server via PLINK (putty). There is NO public private key authentication, the user and the password are in the script. On our ...
12
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1answer
5k views

How to use ssh-agent with multiple (valid) keys and yet choose which one to use?

Let's say there are two keys A and B, both of which are valid for user@host public key authentication. Since authorized_keys is configured for different behaviour depending on the key, ~/.ssh/config ...
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3answers
36k views

sudo over ssh: no tty present and no askpass program specified

I keep getting this error and have tried several ways discussed online to fix this and none are working for me. I have setup SSH keys so when I run 'ssh newton@host.com' it automatically logs me in, I ...
12
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1answer
7k views

Remote desktop over SSH reverse tunnel to replace TeamViewer

I want to open a remote desktop session from my laptop to desktop over my SSH (reverse) tunnel. That should be simple (or at least doable), right? Until now I've been using Team Viewer to log in to ...
11
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3answers
12k views

ssh port forward to access my home machine from anywhere

http://serverfault.com/questions/303937/how-to-make-freebsd-box-accessible-from-internet I want to understand this whole process of port forwarding. I read so many things but failing to understand ...
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2answers
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Understanding SSH tunnels

I have linux (Ubuntu) server which I have root access to through ssh (port 22) only. On that server there is a MySQL database listening on port 3306. Is it possible to use putty (on my machine) and ...
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4answers
339 views

Is my SSH key paired with me as a human, or with my user account on one machine?

In the past few days, I have been trying to acquaint myself with SSH, and I hope that I've understood it. One question remains, however -- is my key associated with me (as the user) or my user ...
11
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6answers
4k views

How to effectively use screen and SSH?

I'd like to configure SSH and screen such that a login will always reattach to a screen session. Ideally, that session would not quit but detach when I press C-d. How can this be achieved? And what ...
11
votes
1answer
18k views

How to wget a file to a remote machine over SSH?

I'd like to basically pipe a wget command to a file on a remote server over SSH. How can I do this? I know I could simply ssh into the server and have it download the file, but I'd much rather use the ...
11
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5answers
25k views

Can a linux user change their password without knowing the current password?

I'm setting up a few ubuntu boxes, and using opscode's chef as a configuration tool. It would be fairly easy to install public keys for each user on each of these servers, and disable password ...
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7answers
8k views

How to rsync files between two remotes?

I would like to transfer files between two remote hosts using on local shell, but it seems rsync doesn't support synchronisation if two remotes are specified as follow: $ rsync -vuar host1:/var/www ...
11
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2answers
8k views

How do I sftp to a server if the username contains @ symbol

I have to sftp to a server to a specific port but the username contains the @ symbol. suppose the user is "user@domain.com" and the ftp server is just "domain.com" I will end with sftp -oPort:8777 ...
11
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1answer
446 views

Remember password for ssh key for some time

I created ssh key. I use it to connect with git repositories. When creating the key, I noticed the prompt that said the password should be hard to guess. Therefore, I came up with 40+ characters-long ...
11
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4answers
28k views

How to copy with SCP between two servers using key auth?

I can log in via SSH using key authentication to SERVER1 and SERVER2. However, I can't copy files between the two servers. Why? How can I copy between them? (the data that I have to copy is bigger ...
11
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2answers
4k views

Detach/reattach an application run on X over SSH?

I have a development server that I leave running all the time, and a development laptop that I turn off/on everyday. I have a GUI application on the server that I'd like to run over SSH -X, and I'd ...
11
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2answers
20k views

ssh and character encoding

When I ssh into my VPS, I have irssi running in screen. When someone sends a unicode character (such as © or €), irssi displays garbage when I use it via the screen in a ssh session. If I connect to ...
11
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7answers
3k views

Why does my Python background process end when SSH session is terminated?

I have a bash script that starts up a python3 script (let's call it startup.sh), with the key line: nohup python3 -u <script> & When I ssh in directly and call this script, the python ...
11
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5answers
11k views

ssh prompts for password despite ssh-copy-id

I've been using public key authentication on a remote server for some time now for remote shell use as well as for sshfs mounts. After forcing a umount of my sshfs directory, I noticed that ssh began ...
11
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5answers
75k views

X client forwarded over SSH “cannot open display: localhost:11.0”

I have enabled X forwarding on remote machine where SSH server is running: # grep -i forward /etc/ssh/sshd_config X11Forwarding yes # On local machine, I have started SSH client with -X flag ...
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3answers
9k views

ssh to private-ip

I have a computer with CentOS (computer A) that configured as has an private ip 10.150.5.141 (with restricted firewall), can access internet and my ArchLinux VPS (computer B) with real ip w.x.y.z How ...
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3answers
4k views

GNU screen freezes trying to reattach

I have several long-running GNU screen sessions. I ssh to the box they're running on and run screen -d -r foo to detach them if they're connected anywhere else, and then attach them in my current ...
11
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1answer
8k views

ssh-agent forwarding for a Vagrant VM

I'm currently looking at setting up a Vagrant environment on my Mac machine, so that I can run vagrant up and it will then install rbenv and ruby and all I need. Then I have a Bash script that will ...
11
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3answers
2k views

How to open a port early in boot process to unlock LUKS via SSH

I have a fully encrypted server running Debian 7 and have set up dropbear and busybox to unlock the LUKS container via SSH (as described in this tutorial and in this U&L answer). Unfortunately, ...
11
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2answers
567 views

A consistent and safe approach to passwordless accounts with SSH

I must admit that I like servers without passwords in some cases. A typical server is vulnerable to anyone who has physical access to it. So in some cases it is practical to lock it physically and ...