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Questions tagged [ssh-keys]

an authorization mechanism for SSH involving public-key cryptography.

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0 votes
2 answers
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Creating an ssh keypair for AWS Lightsail/EC2 instances doesn't work as expected

I've created a fair few SSH keypairs in my days but AWS seems to handle them differently. I'm using AWS Lightsail and it has a notion of 'default' keypairs. This is fine for the 'normal' user that AWS ...
Alistair Ross's user avatar
1 vote
1 answer
118 views

Even if SSH is set up, it always asks for the password when logging into the server

I have an Ubuntu server. I use ssh to access it. It worked fine at first. When user@IP is given along with SSH key, it will log into the server without asking for password. But recently, even with SSH,...
Sachintha madhawa's user avatar
0 votes
1 answer
143 views

ssh from CL using keyfile from Windows client to Linux server

This sort of thing drives me crazy - hopefully obvious solution(s). Have keys on Win 10 laptop, and on one of my Linux servers. If I use puTTY, where I can explicitly browse to the keyfile on the ...
Johnny Canuck's user avatar
0 votes
1 answer
816 views

userauth_pubkey: signature algorithm ssh-rsa not in PubkeyAcceptedAlgorithms after upgrade of OpenSSH

After an upgrade I can no longer log in to my box (FreeBSD 14.0) using RSA key getting: userauth_pubkey: signature algorithm ssh-rsa not in PubkeyAcceptedAlgorithms in /var/logs/auth.log on every ...
sophros's user avatar
  • 111
1 vote
0 answers
218 views

Server host key changing frequently

Im trying to connect to my ubuntu server via ssh from Windows. Unlike my another ubuntu server from same dedicated server hosting, the server host key changing frequently. I get WARNING: REMOTE HOST ...
Mreza Nemati's user avatar
0 votes
1 answer
91 views

Is there a solution to manage users in some systems or at least in linux?

I work somewhere with a lot of Linux and VPS servers. When someone joins the company, other staff members need to add his SSH key to each server; conversely, if someone leaves, all of his SSH keys ...
Mohammad Mahdi's user avatar
0 votes
0 answers
54 views

Custom Linux AMI: How does AWS know where to install account SSH .PEM files when an AMI is provisioned?

We are building a custom AMI from a template EC2 EBS instance snapshot (Oracle Linux 8). This page shows there are many different user names depending on the AMI you choose: https://docs.aws.amazon....
KJ7LNW's user avatar
  • 161
1 vote
1 answer
191 views

Remote Linux server GitHub permission denied publickey issues

I am experiencing publickey permission issues when trying to pull a private repo from GitHub to a remote Linux server. Update Ran ssh -v -o IdentitiesOnly=yes -i ~/.ssh/id_rsa [email protected] command ...
Mike Hermary's user avatar
0 votes
0 answers
155 views

How safely obtain and check host public key for `known_hosts`?

For a newly deployed instance I get the following message for the first time SSH connection: The authenticity of host '[hostname] ([IP address])' can't be established. RSA key fingerprint is [key ...
Eugen Konkov's user avatar
10 votes
4 answers
5k views

How do I prevent users from messing with their own .ssh folder?

I'm administrating a RedHat server where users log in through SSH with private/pub key based authentication. I'd like to prevent them from accidentally changing / deleting /chmoding the content of ...
wecx's user avatar
  • 203
2 votes
1 answer
753 views

How to prevent OpenSSH from creating a new known_hosts file every time it updates it?

It seems that every time I accept a new host key, ssh (I've tested 8.6p1 and 9.3p2) does the following steps: Move the known_hosts file to known_hosts.old; Create a new known_hosts file; Copy the ...
N.I.'s user avatar
  • 123
0 votes
0 answers
141 views

Can not SSH to GUI Ubuntu on Login Screen

I have a laptop with Ubuntu installed, and I've set up SSH using a key, and everything was working fine (I could SSH into the laptop from another computer). Then, I rebooted the laptop, and on the ...
Thuannb96's user avatar
1 vote
2 answers
828 views

How to remove all lines with the same public key from known_hosts?

Let's imagine the following scenario. I have an host key ABCDEF1234 for a given hostname, so my known_hosts file looks like this (unhashed version): example.com ssh-rsa ABCDEF1234 Now I connect to it,...
shodanex's user avatar
  • 242
0 votes
1 answer
71 views

Home directory, user database and key-based authentication

I want to share it NFS share with my users just like the home-directories (traditional way), but I don't want to create the users instead I want to get the server integrated with the github or google ...
AAB's user avatar
  • 13
-2 votes
2 answers
129 views

the theory of SSH public and Private key and its application in realworld machines [closed]

there. In this question, I have a very specific one about public and private keys. So Public keys should be put on the opposite side. For example, if we have a server, the public key of the server ...
Sina M's user avatar
  • 3
0 votes
1 answer
214 views

SSH tries other keys despite specifying a key with -i option

For the same user, I have two keys on the local machine. On the remote server, both keys are in the authorized_keys file. I delete one of the keys in the authorized_keys file. I then try to ssh with ...
ahron's user avatar
  • 375
0 votes
0 answers
170 views

SSH CA-signed key does not work from certain hosts

I've tried to setup CA signed ssh user keys. I got my configuration working on most clients, there seems to be problem on a few specific ones. The key verification fails and they are prompted for ...
Tadeas Vintrlik's user avatar
0 votes
0 answers
13 views

GCP VM instance not showing LESS keys as GCP editing instance metadata?

authorized_keys is missing AFTER I add my ssh key to an instance in GCP so then I connect via browser and authorized_keys is generated with 1. 'TWO keys'. I then click edit on instance and I see 2. '...
Dean Hiller's user avatar
0 votes
2 answers
497 views

How does SSH host verification for github.com provide any value?

Running git clone [email protected]/repo.git warns me of a potential man-in-the-middle attack when GitHub change their SSH key, and that's cool. I then get the new key by running ssh-keyscan -t rsa ...
zoran119's user avatar
  • 101
0 votes
0 answers
265 views

Linux server ssh connection wont authenticate my account using ssh key gen and prompts me for password

I am facing an issue in Ubuntu 22.04.2. where I am unable to SSH into a remote server using a copied public key. I have generated an SSH key pair on my local machine using a bash terminal, and I have ...
Stuff's user avatar
  • 1
0 votes
1 answer
4k views

What is the host key (the one from ssh connection) and how is it different from public-private key pair?

The situation is that I've had a VPS created previously. It was all set up, private-public key authentication, root login turned off, password login turned off. Everything was set up. Then this server ...
michal roesler's user avatar
5 votes
0 answers
14k views

What is the meaning of this line from ssh output: 'Authenticator provider $SSH_SK_PROVIDER did not resolve; disabling'?

Everything works, ssh connects using private-public ssh key pair. Just few things in ssh -v Ora2 output isn't clear for me. This is complete ssh -v Ora2 output: PS C:\Users\roeslermichal> ssh -v ...
michal roesler's user avatar
0 votes
1 answer
926 views

Permission denied (publickey) error when managing GCP machine via Ansible (running on GCP VM) despite successful SSH connection

I deployed two machines to GCP via Terraform. Let's call them control-host and target-host. I want to manage the target-host via Ansible installed on the control-host. Unfortunately, I keep getting ...
mångata's user avatar
  • 109
4 votes
2 answers
3k views

Why I can not ssh to my Vagrant host? [email protected]: Permission denied (publickey)

I created 5 VMs for my project vagrant status Current machine states: master-1 running (virtualbox) master-2 running (virtualbox) master-3 running (...
MikiBelavista's user avatar
0 votes
1 answer
43 views

SSH key for 2 client users to 1 server user

If this is a duplicate, I'm sorry. I have searched my case but I couldn't find the right scenario that resembles my situation, although I thought that this situation must have come up before for ...
antimatter's user avatar
1 vote
1 answer
583 views

Validate all public keys in authorized_file

In my authorized_file i have multiple public keys against one private key. Now i want to add a task in ansible which will validate that all public keys are valid keys and good for connection. My aim ...
Sakshi Arora's user avatar
2 votes
2 answers
915 views

Avoid SSH AgentForwarding of incompatible keys

Good morning, I have one ed25519-sk key (using a hardware token), which I need only on my personal machine for some high security servers (all Debian). This key type is supported by OpenSSH 8.3+. We ...
Powerriegel's user avatar
0 votes
1 answer
593 views

sshd not providing ecdsa/ed25519 host key algos

we have setup'd a bastion that only responds with the ssh-rsa host key algorithm when querying: ssh-keyscan bastion.ops.dev.xxx.com # bastion.ops.dev.xxx.com:22 SSH-2.0-OpenSSH_7.4 # bastion.ops.dev....
hotzen's user avatar
  • 133
1 vote
1 answer
3k views

Adding my SSH key to new user with only SSH access through key

I'm quite new to this, and I've looked through questions but haven't found one that quite matches my problem, or rather I didn't sufficiently understand them to be able to solve this issue. I have a ...
Jack Avante's user avatar
0 votes
0 answers
1k views

ssh illegal option while trying to connect to remote server

trying to ssh from my macbook pro, to a remote server, ssh ayan@ServerIPAddress gives the following error ssh: illegal option -- ? usage: ssh [-46AaCfGgKkMNnqsTtVvXxYy] [-B bind_interface] ...
Ayan Mitra's user avatar
0 votes
1 answer
401 views

Needs a clarification for the ssh-copy-id command

Say I have two computers connected to the same Wifi network. Let's call them computer-A & computer-B. I am using computer-A, I can ping computer-B without issues. Now, on computer-A, I have ...
user842225's user avatar
2 votes
1 answer
187 views

User account auto-creation using SSH certificate authentication

My SSH server is configured to use certificate authentication, so it will trust anyone who presents a certificate issued by the user CA when they connect. For reasons related with audit logs, I don't ...
Jorge Carpio's user avatar
0 votes
1 answer
95 views

Install SSH key in an account that has no "usable" shell

A remote SSH server has a guest account with a known, non-blank password, that when logged in directly executes a text-based terminal game (not sure if via command, shell, or another method). The ...
MestreLion's user avatar
  • 1,723
0 votes
1 answer
48 views

Github Deploy Key Pattern

My Deployment Pattern I have a setup as shown in the diagram above, where have a github account which owns a number of private repositories. I have a number of machines in the field that each include ...
Kevin John's user avatar
2 votes
1 answer
380 views

Use OpenSSH to make a key exchange with NTRU Prime

I would like to make a key exchange for a symmetric key from the client to the server with the NTRU Prime algorithm (for test reasons). I already installed OpenSSH 9.1 on both sides and checked ...
bilaljo's user avatar
  • 123
6 votes
3 answers
5k views

Why the RHEL8 system do not generate SSH host keys automatically when missing?

On the RHEL 8 and previous it is usual, that the SSH host keys in /etc/ssh are generated automatically by sshd service when missing. Usually there should be: /etc/ssh/ssh_host_ecdsa_key /etc/ssh/...
Jaroslav Kucera's user avatar
6 votes
1 answer
3k views

How to ssh-copy-id through a jump-host? Something similar to the -J option with ssh command

I use a jump host to connect to the remote servers through SSH. I use the following linear command for the connection. ssh -J jumpuser@jumphost:2455 remoteuser@remotehost It works fine. But for new ...
Ajaib Singh's user avatar
0 votes
1 answer
77 views

Cannot add passwordless private key with ssh-add on remote server

I can add a passwordless id_ed25519 file locally using ssh-add -k, but not on my remote server. Locally: ☁ ~ ssh-add -l The agent has no identities. ☁ ~ ssh-add -k ~/.ssh/id_ed25519 Identity added:...
iftheshoefritz's user avatar
1 vote
1 answer
2k views

Why do i need to restrict permissions on a PEM key?

I have a .pem key file that i use to ssh to my ec2 server. I've moved this key file to an encrypted external SSD disk. This has caused the owner of the pem key to be set to 'everyone'. When i try to ...
Maurice's user avatar
  • 137
12 votes
2 answers
5k views

ssh how to allow a very limited user with no home to login with pubkey

I have a very restricted user in my ssh server created with --no-create-home and --shell /bin/false. I know I can define authorized_keys file in sshd_configs for the user's public key. But how can I ...
Mojtaba Rezaeian's user avatar
1 vote
0 answers
839 views

Connection closed by remote host when copying client public key to sftp server

I want to copy the client public keys for a container to a remote sftp server and after that attempt do some uploads to the server via bash script(the bash script will be invoked when the container ...
Golide's user avatar
  • 143
0 votes
1 answer
912 views

back up and restore host ssh_keys using cloud init autoinstall ubuntu

I am trying to automate VM installations for ubuntu 22.04 using autoinstall,cloud-init, qcow2 and virt-install. When I am reinstalling the OS on the same qcow2 file, I have a script that is run in ...
mavenHawk's user avatar
0 votes
0 answers
60 views

Tentative of shh->rsync to wrong IP; potential security risk?

I have set up a little RPI backup 'server' (with rpi OS) on my LAN. I use it to create a backup of my main personal machine data using rsync, and I reach it from outside my network through SSH (key-...
maxechstack's user avatar
0 votes
2 answers
566 views

After install last version on ubuntu server 22 i can`t make ssh key connect to remote server

I did all the steps to create the key as I normally do: ssh-keygen -t ed25519 next ssh-copy-id -i /home/derbauer/.ssh/id_rsa.pub -p 12122 [email protected] here everything goes normally But in the ...
Petar Petrov's user avatar
3 votes
3 answers
981 views

Administrative access to a server via SSH key

Is it a good idea to set the SSH key directly for the root user for administrative access to a server? Or is it better to use another user for SSH access via SSH key, followed by sudo command? Is the ...
phanaz's user avatar
  • 422
0 votes
1 answer
2k views

SSH Permission denied (public key)

I am trying to create my own SSH key to connect from one VM A to another VM B (both are Debian/bullseye64 systems). Both VMs are configured to be on a public network using vagrant on my system with A ...
Ironscar's user avatar
0 votes
1 answer
154 views

Pull ssh key from github server

Many users have their own public ssh keys on github. Is there an easy way to get it knowing someone else's username? I know it's possible - the ubuntu installer gets the keys somehow - but I can't ...
undefine's user avatar
  • 1,076
0 votes
1 answer
2k views

SSH permission denied

I have problem logging using ssh to company server. I have my local ~/.ssh/config; Host target HostName xx.yy.zzz.aaa User abcd IdentityFile ~/.ssh/id_ed25519 IdentitiesOnly=yes I have other ...
sjiamnocna's user avatar
2 votes
1 answer
3k views

SSH2 fails authentication with a working key converted with PuttyGen (due to deprecated ssh-rsa?)

I have an EC2 instance authenticated with a key-pair generated by AWS. With Putty, I can connect to the instance by providing the private key in a PPK file. When I try to use SSH2 (via one of the ...
sebf's user avatar
  • 123
1 vote
0 answers
30 views

no passphrase asked on copied ssh-key

I used an id_ed25519 key on a Debian Bullseye to connect to our remote servers, which had a passphrase. My laptop crashed so I recovered the key from a backup and started using it on an Ubuntu 22.04. ...
Jakke's user avatar
  • 141

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