Generate Etc Ssh Ssh_host_dsa_key

admin 15.04.2020

9ab.netlify.com › Generate Etc Ssh Ssh_host_dsa_key █ █ █

Ssh-keygen -b 1024 -t ecdsa -f /etc/ssh/sshhostecdsakey The first command will automatically generate all the required keys. But the second command will be helpful if you want to create only one of those keys and not all. Generating SSH CA Certificate Signing Keys. On the server designated to be the CA, generate two keys for use in signing certificates. These are the keys that all other hosts need to trust. Choose suitable names, for example causerkey and cahostkey.

Ssh Key Example
Ssh Generate Key Ubuntu
Ssh Update Host Key

My Google is failing me.
So, you know when you start up a new Linux server with OpenSSH-Server for the FIRST time, you generate a server key pair? Anyone know what script runs that?
What would happen if you re-ran the script on a machine that's been up and connected for a while? If no one knows the answer to the second one, I'll try it with some throwaway VMs.
Note: I am not talking about ssh-keygen -t dsa/rsa for normal users, I am talking about SERVER ssh keys.
Here's an example on a Debian install:

SSH keys can serve as a means of identifying yourself to an SSH server using public-key cryptography and challenge-response authentication.The major advantage of key-based authentication is that in contrast to password authentication it is not prone to brute-force attacks and you do not expose valid credentials, if the server has been compromised. Sep 21, 2011 Tutorial: Setting up SSH keys Posted on September 21, 2011 September 21, 2011 by roy Using SSH is a great way to remotely manage a server and to securely transfer data to and from it.

Setting up openssh-server (1:5.5p1-6+squeeze1) ..
Creating SSH2 RSA key; this may take some time ..
Creating SSH2 DSA key; this may take some time ..
Restarting OpenBSD Secure Shell server: sshd.

## sshdconfig IgnoreUserKnownHosts no For user instructions, see How to Generate a Public/Private Key Pair for Use With Secure Shell. Copy the client's public key to the server. The host keys are stored in the /etc/ssh directory. The keys are typically generated by the sshd daemon on first boot. A host key is a cryptographic key used for authenticating computers in the SSH protocol. Host keys are key pairs, typically using the RSA, DSA, or ECDSA algorithms. Public host keys are stored on and/or distributed to SSH clients, and private keys are stored on SSH servers.

How do I regenerate OpenSSH sshd server host keys stored in /etc/ssh/ssh_host_* files? Can I safely regenerate ssh host keys using remote ssh session as my existing ssh connections shouldn’t be interrupted on Debian or Ubuntu Linux? How do I regenerate new ssh server keys? How to regenerate new host keys on a Debian or Ubuntu Linux?
Ssh

Ssh Key Example

[donotprint][/donotprint]To regenerate keys you need to delete old files and reconfigure openssh-server. It is also safe to run following commands over remote ssh based session. Your existing session shouldn’t be interrupted.

Why regenerate new ssh server keys?

Most Linux and Unix distribution create ssh keys for you during the installation of the OpenSSH server package. But it may be useful to be able re-generate new server keys from time to time. For example, when you duplicate VM (KVM or container) which contains an installed ssh package and you need to use different keys from cloned KVM VM guest/machine.

Steps to regenerate OpenSSH host keys on Linux

Let us see all steps

Step 1 – Delete old ssh host keys

Login as the root and type the following command to delete files on your SSHD server:
# /bin/rm -v /etc/ssh/ssh_host_*
Sample outputs:

Ssh Generate Key Ubuntu

Step 2 – Debian or Ubuntu Linux Regenerate OpenSSH Host Keys

Now create a new set of keys on your SSHD server, enter:
# dpkg-reconfigure openssh-server
Sample output:

You just regenerated new ssh server keys. You need to restart ssh server:
$ sudo systemctl restart ssh
OR
$ /etc/init.d/ssh restart

Step 3 – Update all ssh client(s) known_hosts files

Finally, you need to update ~/.ssh/known_hosts files on client computers, otherwise everyone will see an error message that read as follows:

Either remove host fingerprint or update the file using vi text editor (command must be typed on client machine):
$ ssh-keygen -R remote-server-name-here
Now login using the ssh command:
$ ssh vivek@server1.cyberciti.biz

Conclusion

You just regenerated OpenSSH Host Keys on a Debian or Ubuntu Linux using the dpkg-reconfigure command. For more info see the man page or this wiki page here:
$ man dpkg-reconfigure $ man sshd