I have updated my system with sudo apt-get update.
There was a update of PAM (The Pluggable Authentication Module). I don't remember the message, but there was like a pink screen and I decided to choose no (sorry for that poor explanation).
After that the update continues until something like ssh stop/waiting and then nothing happens. I couldn't cancel this und decided to reboot my Ubuntu Server (14.04 LTS).
After that I cannot connect with a user to this machine with ssh -X user#host. Only the owner can connect. But no other user.
With ssh -v user#host I get the error
debug1: Authentications that can continue: publickey,password
Permission denied, please try again.
Then I recognized that there are a lot of missing files in my ~/.ssh/ directory.
There is only the file known_hosts. I think there should be also the files: Readme, authorized_keys, bup, deprec, id_dsa, id_dsa.pub.
Do I have to reinstall ssh?
You do not need to reinstall ssh.
Many of those files are generate as you use ssh and related commands.
The most important files in my experience (which you will generate) are:
authorized_keys: contains public keys which are authorized to connect.
id_dsa and id_dsa.pub (or id_rsa, etc.) are the private key and public key (with .pub suffix) are the keys you offer when attempting a connection. These are generated by executing ssh-keygen.
Also, config is nice to use, but also not necessary. see man ssh_config.
Restoring connections from other machines
It appears you've lost the authorized_keys file you had. If you wish to continue connecting via publickey from other machines, you will need to put the public key from the other machine into your authorized_keys file.
Ensure authorized_keys file exists (if not: touch ~/.ssh/authorized_keys)
Copy the public key (id_rsa.pub for example) from the machine[s] you will be connecting from.
Paste the public key[s] into authorized_keys, one per line.
Related
I used to have ssh connection to my server from bash console on Linux subsystem in Windows 10.
I reinstalled Windows and moved id_rsa, id_rsa.pub and known_hosts to exact the same folder where it was on previous system.
But now ssh dont see keys and ends up with error Permission denied (publickey).
But I still can connect using CMD with those keys so issue is not dependig on key file.
On previous system the ssh keys was stored on path: C:\Users\My_Win10_User_Name\AppData\Local\Packages\CanonicalGroupLimited.Ubuntu18.04onWindows_79rhkp1fndgsc\LocalState\rootfs\home\My_Linux_Subsystem_User_Name\.ssh so I moved keys to this folder.
What steps should be taking to make ssh on Linux subsystem works again with my old keys?
ssh requires permissions to be correct. Your ~/.ssh directory must be 0700, and the files inside must be 0600. You also don't mention your ~/.ssh/authorized_keys file, which must contain your public key file (the contents of id_rsa.pub.) That file, too, must be chmoded to 0600.
Requirement- Connecting SFTP server from local windows machines using WinSCP with keys
Technical- I have Azure VM(Windows 2012 server R2) in which Cygwin64 is installed for SFTP.
I want to connect SFTP server using RSA authentication i.e using keys.
I have edited the sshd_config file for RSA authentication. In cygwin64 folder I have also created .ssh folder and under that Authorized_keys file.
From local machine using putty I have generated Public and private keys and this public key I have entered in Authorized keys file but when I am trying to connect with that Private key it is saying "Server refused our key"
I have entered in Authorized keys file but when I am trying to connect
with that Private key it is saying "Server refused our key"
If you see this type of message, the first thing you should do is check your server configuration carefully. Common errors include having the wrong permissions or ownership set on the public key or the user’s home directory on the server.
Maybe you can follow those steps to setup CYGWIN authenticate with private key:
1.Install GYCWIN (OpenSSH and cygrunsrv)
2.configure sshd use this command ssh-host-config -y
3.Start SSHD service with this command cygrunsrv --start sshd
4.Add your public key to authorized_keys(we can copy public Key to this file):
jason#jasonvm ~/.ssh
$ ls -a
. .. authorized_keys id_rsa id_rsa.pub id_rsa1 known_hosts
$ cat authorized_keys
ssh-rsa AAAAB3Nxxx.......xxxxzaAVbeVFw==
jason#jasonvm ~/.ssh
$ pwd
/home/jason/.ssh
By the way, if you can't find this directory, you can use ssh-keygen.exe command to create this directory /home/user/.ssh, if you can't find this file authorized_keys, we should create it, and run this command chmod 600 authorized_keys
Afther that, we can use other Linux VM to SSH or SFTP this VM(we should open port 22 on Azure NSG inbound rules).
If you want to use winscp to login this VM, we should convert private key to .ppk. In this way, we can use this key to login this SFTP.
Note:
we can use winscp to convert .key to .ppk.
For test, you may try to use Putty to login azure vm with your private key, to make sure you are using the right private key and public key.
Update:
We can add open ssh and sftp like this:
I created a new EC2 Amazon Linux instance. I want to allow a developer to SSH into the EC2 instance. To test this, I'm trying it from my windows computer. I have followed the instructions in the link below but I can't get SSH (Putty) to connect using the key pair I'm generating.
I'm following the instructions here as reference
and here
After logging into EC2 as ec2-user using FireSSH and the pem generated by AWS, I use SSH to run the following commands to create a new user, .ssh directory, and permissions.
[ec2-user ~]$ sudo adduser newuser
[ec2-user ~]$ sudo su - newuser
[newuser ~]$ mkdir .ssh
[newuser ~]$ touch .ssh/authorized_keys
[newuser ~]$ chmod 600 .ssh/authorized_keys
[newuser ~]$ vim .ssh/authorized_keys
Then I paste a public key into authorized_keys using vim. I will explain where I get the public key in the next step.
ssh-rsaAAAAB3NzaC1yc2EAAAADAQABAAABAQClKsfkNkuS ....
To create the public key which I pasted in the previous step I followed the steps in this reference starting at "Generating an SSH Key"
I copied the public key from PuttyKeyGen which is showed in the box labeled "Public key for pasting into OpenSSH authorized_keys". Then I pasted that into the .ssh/authorized_keys file on my EC2 instance in the newuser directory.
I log out of the SSH client on EC2. Then I try to login with Putty using the newly created private key on my windows machine. I use the newuser login name. I get this error in Putty: server refused our key. There is also a dialog box that says Disconnected: No supported authentication methods available {server sent: publickey)
What am I doing wrong in these steps?
I did two things different and it works now. It's probably the number of bits that made it work.
I generated a new key pair using PuttyGen but I specified SSH-2 RSA with 1024 bits instead of the default that PuttyGen was putting in which was like 2048.
When I logged back into EC2 with my SSH I pasted the public key using nano instead of vim.
Always use ec2-import-keypair features to verified whether it is GOOD for EC2 instance. It the import works, then it is good, otherwise, regen a compliance keypair. If you simply copy a keypair that is not compliance , you will run into trouble.
Here is the document for import key pair
OpenSSH public key format (the format in ~/.ssh/authorized_keys)
Base64 encoded DER format SSH public key file format as specified in
RFC4716 DSA keys are not supported. Make sure your key generator is
set up to create RSA keys.
Supported lengths: 1024, 2048, and 4096.
I have two Amazon EC2 Ubuntu instances. When I connect to one of them, I can do
ssh ubuntu#54.123.4.56
and the shell uses the correct keyfile from my ~/.ssh directory.
I just set up a new instance, and I'm trying to figure out how to replicate that behavior for this new one. It's a minor thing, just driving me nuts. When I log in with:
ssh -i ~/.ssh/mykey.pem ubuntu#54.987.6.54
it works fine, but with just
ssh ubuntu#54.987.6.54
I get:
Permission denied (publickey).
I have no idea how I managed to get it to work this way for the first server, but I'd like to be able to run ssh into the second server without the "-i abc.pem" argument. Permissions are 600:
-r-------- 1 mdexter mdexter 1692 Nov 11 20:40 abc.pem
What I have tried: I copied the public key from authorized_keys on the remote server and pasted it to authorized_keys on the local server, with mdexter#172.12.34.56 (private key) because I thought that might be what created the association in the shell between that key and that server for the shell.
The only difference I can recall between how I set up the two servers is that with the first, I created a .ppk key in PuTTy so that I could connect through FileZilla for SFTP. But I think SSH is still utilizing the .pem given by Amazon.
How can I tell the shell to just know to always use my .pem key for that server when SSHing into that particular IP? It's trivial, but I'm trying to strengthen my (rudimentary) understanding of public/private keys and I'm wondering if this plays into that.
You could solve this in 3 ways:
By placing the contents of your ~/.ssh/mykey.pem into ~/.ssh/id_rsa on the machine where you are ssh'ing into 2nd instance. Make sure you also change the permissions of ~/.ssh/id_rsa to 600.
Using ssh-agent (ssh-agent will manage the keys for you)
Start ssh-agent
eval `ssh-agent -s`
Add the key to ssh-agent using ssh-add
ssh-add mykey.pem
Using ssh-config file:
You could use ssh config file. From the machine where you are trying to ssh, keep the following contents in the ~/.ssh/config file (make sure to give this file 600 permissions):
Host host2
HostName 54.987.6.54
Port 22
User ubuntu
IdentityFile ~/.ssh/mykey.pem
Once you do that now you could access do the ssh like this:
ssh host2
After performing any of the above steps you should be able to ssh into your second instance with out specifying the key path.
Note: The second option requires you to add the key using ssh-add every time you logout and log back in so to make that a permanent injection see this SO question.
My main development box uses Linux Mint.
When I am physically at the computer I can do remote operations like git fetch with no problem.
The user I log-in as is "jonbri".
> whoami
jonbri
In ~/.ssh (/home/jonbri/.ssh) is my private key (/home/jonbri/.ssh/jonbri) and public key (/home/jonbri/.ssh/jonbri.pub).
But when I am at another computer, for example another Linux Mint computer, and on the command-line I open a ssh remote shell to my main computer, when I try operations such as git fetch, it looks like the keys in ~/.ssh are not being picked up.
Here's what I see (with pwd being the root of the git repo):
> git fetch
Password:
Then, even no matter which password I enter it doesn't work.
To enable the ability to open a remote ssh shell I used apt-get to install open-ssh-server and open-ssh-client.
Any ideas why my keys aren't being picked up when inside a remote ssh shell.
SSH is likely expecting the standard names of id_dsa for your private key and id_dsa.pub for your public key.
From the github documentation:
Check the directory listing to see if you already have a public SSH key.
The default public key file names are:
id_dsa.pub
id_ecdsa.pub
id_ed25519.pub
id_rsa.pub