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Questions tagged [ssh]

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.

Secure Shell or SSH is a network protocol that allows data to be exchanged using a secure channel between two networked devices. Used primarily on Linux and Unix based systems to access shell accounts, SSH was designed as a replacement for Telnet and other insecure remote shells, which send information, notably passwords, in plaintext, rendering them susceptible to packet analysis.

It's important to note that there are two versions of SSH (1 and 2), and that version 1 is no longer considered secure, and should be replaced by version 2 where ever possible.

More information, including the more notable SSH-1 vulnerabilities, can be found at the Wikipedia page for SSH.

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How to use openssh sftp command with a RSA/DSA key specified from the command line

The Openssh ssh and scp command provied an -i command line option to specify the path to the RSA/DSA key to be used for authentication. Looking at the sftp man pages I was not able to find a way to specify the RSA/DSA key. I am looking for a way to…
Adi Roiban
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Using Same SSH Private Key Across Multiple Machines

I've got a Github repo I want to access from two different Linux machines. For the first machine, I followed Github's instructions for generating SSH keys, and added the resulting public key to Github. This client works fine. For the second…
Yarin
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How do I sudo over sshfs?

On my local host alpha I have a directory foo that is mapped via sshfs to host bravo as follows: $ sshfs charlie@bravo:/home/charlie ~/foo However, on host bravo there is another user, delta, that I want to sudo /bin/su as, so that I can do work in…
dirtside
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What does "Normal Shutdown, Thank you for playing [preauth]" In SSH logs mean?

Recently, My SSH log summaries for my Ubuntu 12.04 servers in Logwatch have started showing entries for "11: Normal Shutdown, Thank you for playing [preauth]" along with the "11: Bye Bye [preauth]" and "11: disconnected by user" messages they had…
Dave Stern
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What are best practices for managing SSH keys in a team?

I work with small teams (<10) of developers and admins with the following characteristics: Most members of the team have >1 personal computer, most of which are portable Team members have access to 10-50 servers, usually with sudo I think this is…
Evan Prodromou
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Can't get SSH public key authentication to work

My server is running CentOS 5.3. I'm on a Mac running Leopard. I don't know which is responsible for this: I can log on to my server just fine via password authentication. I've gone through all of the steps for setting up PKA (as described at…
Trey Parkman
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sshd service fails to start

I'm not sure why it isn't starting or why its preventing me from connecting, i get this error: sshd.service - OpenSSH Daemon Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled) Active: failed (Result: start-limit) since Wed…
aCoolBean
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Rsync command issues, owner and group permissions doesn´t change

I´m trying to set owner and group via rsync and it doesn't seem to be working. This is the command: sudo rsync -rlptDvz --owner=cmsseren --group=cmsseren /home/serena/public_html/ -e ssh root@ip:/home/cmsseren/public_html2/ The files sync correctly…
Arnoldo Bazaldua
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How to enable SSH X11 forwarding through additional server?

I have hosts A,B and C. From host A I can access through ssh only B. From B I can access C. I want to be able to run X11 programs on C and forward display to A. I tried this: A$ ssh -X B B$ ssh -X C C$ xclock Error: Can't open display: But it…
lexsys
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SSH session drops - Does the command continue executing?

If I was running a command before the SSH connection was dropped, will the command continue executing?
Miko
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Slow ssh login - Activation of org.freedesktop.login1 timed out

On one of my servers I've noticed really delay on SSH logins. Connecting using the ssh -vvv options the delay occurs at debug1: Entering interactive session. extract of connection: debug1: Authentication succeeded (publickey). Authenticated to…
Alasdair
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What is the meaning of an equal sign = or == at the end of a SSH public key?

I just noticed that most of the ssh pubkeys in my authorized_keys end on == or = E.g. ssh-rsa…
Lukas Loesche
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What's best practice for communication between Amazon EC2 instances?

I've been setting up Amazon EC2 instances for an upcoming project. They are all micro instances, running Ubuntu Server 64bit. Here's what I've setup so far: Web Server -- Apache Database Server -- MySQL Development Server -- Apache & MySQL File…
ks78
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Specify SSH Port for Git

I use a non-standard ssh port (1234) for most of the servers I connect to. So in my ssh config file I have: Port 1234 But github.com uses port 22. When I try to connect to github it obviously tries to use port 1234. Right now I have to edit my…
James Ward
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Best system for managing ssh keys?

I've got several client computers (i.e. laptops, desktops, etc.), and I connect to several server machines that I manage, and I log into them all via SSH. I can imagine several schemes of managing ssh keys that would make sense, and I'm curious…
slacy
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