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Questions tagged [openssh]

Questions about the OpenSSH implementation of the ssh protocol.

OpenSSH is a free version of the SSH connectivity tools. It is developed by the OpenBSD Project and in countries that permit cryptography export. It is freely useable and re-useable by everyone under a BSD license.

OpenSSH is developed by two teams. One team does strictly OpenBSD-based development, aiming to produce code that is as clean, simple, and secure as possible. The other team then takes the clean version and makes it portable (being then "less clean") to make it run on many operating systems -- the so-called -p releases (ie "OpenSSH 4.0p1").

Further reading

784 questions
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ssh server: reasons for sudden "Connection closed by remote host"

One of my ec2 servers has stopped receiving ssh connections. The OS is Ubuntu server 8.04, and the ssh server is the standard openssh-server. After months of uptime, I tried to connet to it today, and got the following…
Adam Matan
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How to disable password prompt from ssh client side?

I have a script that relies on public/private key ssh authentication. The problem is that some systems are misconfigured and do not have the proper ssh public/private key trust set up. When that happens ssh ask me for a password blocking the…
Red Cricket
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SSH stopped working after a server update? What happened?

I have been using PKI based SSH connections for over 10 years. Suddenly, after a server update - some of the connections stopped working. I am using the same PKI keys I have used for years (each server has it's own keys, I have a small set of…
Michael Felt
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2 answers

What are the various levels in ssh -vvv: debug1, debug2, debug3

Is each a different side of the connection or a deeper layer of logging. I am interested because of, for example, this excerpt from a vvv output debug3: send packet: type 30 debug1: expecting SSH2_MSG_KEX_ECDH_REPLY Connection reset by nnnn port…
Stephen Boston
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Why not set OpenSSH's MaxSessions to 1000000?

I have my SSH client configured to multiplex my sessions: Host * ControlMaster auto ControlPath ~/.ssh/sockets/%r@%h-%p ControlPersist 600 I'm occasionally bumping into the default OpenSSH server side MaxSessions limit of 10. The obvious answer is…
Alan De Smet
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6
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1 answer

ssh config file with multiple ssh versions

I really like the "Match" keyword that was added to OpenSSH around version 6.5, and I make heavy use of it in my .ssh/config file. But that config file is in my NFS-ed home, and so is referenced when I log in to any of several computers in our…
Phil
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1 answer

Can an OpenSSH server forward inbound traffic to another server?

In my current work setup, I have: Windows 7 laptop Ubuntu virtual host / SSH Windows 2k8 guest I'd like to be able to RDP from my laptop into the Windows guest without having to open additional ports or have Windows RDP directly exposed to the…
Ivan
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5
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1 answer

OpenSSH's SSH client not respecting order of IdentityFile settings

How can I specify the order in which OpenSSH's SSH client (OpenSSH_7.5p1, OpenSSL 1.0.2k 26 Jan 2017; Git for Windows v2.11.1) offers the public/private key pairs to a SSH compliant daemon such as Apache Mina SSHD (Gerrit Code Review service). My…
Tim Friske
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4
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1 answer

Master refused session request: Permission denied

I'm trying to set up SSH multiplexing, but I'm running into an error, and there are insofar 0 hits on Google for the exact error message. I created ~/.ssh/config with the contents: Host * ControlPath ~/.ssh/master-%r@%h:%p Then, I created the…
Vladimir Panteleev
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4
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1 answer

Can ping but can't do ssh

I am able to ping my friend but not able to do ssh. Why so? He is using a modem. I thought there might be some firewall enabled. I told him to type #iptables -F He did that, but still I am not able to do ssh on his system. How can I do this? I get…
Chankey Pathak
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3
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1 answer

how do i fix SSH Permission denied?

I followed all the steps and created the /home/dave/.ssh folder. I then ran: ssh-keygen -t rsa –P "" And got: too many arguments. I tried: ssh-keygen -t rsa –P and it jumped back to the prompt. I then tried: $ cat $HOME/.ssh/id_rsa.pub >>…
Dave
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3
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Restrict ssh by host key fingerprint

Is there a way with OpenSSH (ssh) to specify the expected host key fingerprint as a command-line argument so that a connection will only be allowed if the key fingerprint sent by the server matches the one given as a command line argument ? I am…
starfry
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2
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ssh keys in /etc/ssh keep being regenerated on startup

I have set up a Raspian Buster OS with /etc in its own partition. Whenever I reboot the machine, the ssh keys in /etc/ssh keep being regenerated. I have checked jounrnalctl log, but it doesn't show anything. Another strange aspect is when the keys…
Scott
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1 answer

What the -I certificate_identity ssh-keygen option is for?

I'm following this tutorial to validate a SSH server, in theory I should use a private key provided by an authoring server to sign the SSH pub key, but I don't understand the role of the -I option and what value should it have: ssh-keygen…
Daniele
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1 answer

OpenSSH-Server: How can I remotely set the client's side window title?

I have an OpenSSH server running under Ubuntu 14.04LTS. I'm connecting to it from a Windows 7 machine via PuTTY's SSH client. I have found this option on Putty client named Disable remote-controlled window title changing:                ... that,…
Sopalajo de Arrierez
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