I am planning to do a fresh install of ubuntu 11.10 in my system. Before that i have setuped key based ssh authentication in this machine. Is it possible to take backup of those ssh keys, so that i can use that in my new installation. Or else i must setup keybased ssh authentication again? If i can take backup, what are the files i need to copy? Can someone explain it in detail pls. Thanks in advance.
Here is Solutions:
We have many solutions to this problem, But we recommend you to use the first solution because it is tested & true solution that will 100% work for you.
Responding to SSH only… yes, you can keep your keys.
I can’t think of any topic on which to expound about that, though. It is straight forward: if your username is
karthick, then the keys are located in a hidden directory here:
id_rsa.pub file contains the public key used to authenticate. But there are other files to keep – all of them, really, such as
known_hosts for example. The MOST IMPORTANT is
id_rsa (note the lack of
.pub) as this is your private key. Back up each user. For example, if you set up SSH for
/root/.ssh as well. And so on for as many accounts as you have for this reason.
Cryptographic keys which you may want to backup.
Each user has a directoy ~/.ssh, which typically contains the following files:
1) id_dsa private key of this user (different filename for rsa keys) 1) id_dsa.pub public key of this user 2) authorized_keys public key of other users (or same user on other machines) config personal configuration known_hosts host keys of other machines
Additionally, in /etc/ssh/, you will find:
3) ssh_host_dsa_key 3) ssh_host_dsa_key.pub 3) ssh_host_rsa_key 3) ssh_host_rsa_key.pub
Those are the host keys, keys identifying this computer.
You certainly want to backup all private and public keys. We call the machine in question home and the user [email protected] Same person has an account [email protected] and uses key-based login in both directions. What would happen if you loose any of the key files:
- You loose the identity of [email protected]
ssh [email protected]from home will no longer work with key based auth.
- [email protected] loose the right to login to home with his key.
ssh [email protected]will no longer work from remote with key based auth.
- You loose the identity of the host. [email protected] will see a warning that host keys have changed when trying
ssh [email protected]. Depending on the configuration this will prevent him from logging in.
Note: Use and implement solution 1 because this method fully tested our system.
Thank you 🙂