ssh-add is a helper program for ssh-agent.
Enable root login over SSH. Now that virt-v2v is installed, the conversion server must be prepared to accept P2V client connections. The P2V client connects to the conversion server as root using SSH, so root login over SSH must be allowed on the conversion server.
ssh-add adds RSA or DSA identity files to the ssh agent. For ssh-add to work properly, the agent should be running, and have the SSH_AUTH_SOCK environment variable set.
- Fix “Could not Open” Error (and Add Default RSA/DSA identities) By default, when you try to execute.
- The key exchange in SSH protocol 1.5 uses PKCS#11.5 public key encryption standard to make the key exchange between client and server upon connection. An attack (see 1 and 2) discovered by David Bleichenbacher on PKCS#11.5 can be exploited to recover arbitrary session keys.
1. Fix “Could not Open” Error (and Add Default RSA/DSA identities)
By default, when you try to execute the ssh-add command, you might get “Could not open a connection to your authentication agent.” error message as shown below.
The reason is ssh-agent is not running.
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But, if you start the ssh-agent as shown below, you’ll still get the same error.
In order to fix the issue, you should start the ssh-agent as shown below.
Now, when you execute the ssh-add, it will add the ~/.ssh/id_rsa, ~/.ssh/id_dsa and ~/.ssh/identity files to ssh-agent, and will not throw any error message.
2. Display the entries loaded in ssh-agent
Use either -l or -L as shown below to display all the RSA and DSA entries that are currently loaded into the ssh-agent.
The following examples shows that there are two entries currently loaded to the ssh-agent.
3. Delete all entries from ssh-agent
Use option -D as shown below to remove all the ssh entries from the ssh-agent.
4. Delete specific entries from ssh-agent
Using -d option, you can specify exactly what entries you like to delete.
The following example will remove only the default RSA entry from the ssh-agent.
5. Lock (or) Unlock the SSH Agent
You can lock the ssh agent as shown below using -x option. Once you lock the agent, you cannot add, delete, or list entries in the ssh agent without a password.
After locking, if you try to add, you’ll se SSH_AGENT_FAILURE message as shown below.
To unlock an agent, use -X option as shown below. Make sure you enter the same password that you gave while locking the agent. If you give a wrong password, you’ll set “Failed to unlock agent.” message.
Overview¶
Secure shell comes disabled by default in openmediavault, when installing openmediavault on top aDebian installation, the systemd unit will be disabled after the serverpackages are installed. Just login into web interface to re-enable the ssh service.
The configuration options are minimal, But is possible to:
- Disable the root login
- Disable password authentication
- Enable public key authentication (PKA)
- Enable compression
- Enable tunneling (for SOCKS and port forward)
An extra text field is provided to enter more options. Chrome for mac os 10.7. Examine first thefile
/etc/ssh/sshd_config
before adding extra options otherwise theoption will not be applied. In that case is necessary change the environmental variable.Normal openmediavault users created in the web interface can access the remote shell byadding them to the ssh group. Using PKA for users requires keys to be addedto their profile, this is done in the Users section. The key has to beadded in RFC 4716 format. To dothat run:
Paste the output in the users profile at
AccessRightManagement|Users|<USERNAME>|Edit|PublicKeys
.The number of keys per user is unlimited. A public key in RFC 4716 looks like this:
The comment string is very important. This will help track down when is necessary to revoke the key in case it gets lost or stolen.
Admin Tasks¶
If root login has been disabled and need to perform administrative tasks in the terminal, swap to root by typing:
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To use sudo for root operations add the user to the sudo group.
The SFTP server comes enabled by default for root and ssh group. So POSIX folder permissions apply to non-root users accessing via SFTP.
Note
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- Forward in router/firewall a port different than 22. This will minimize bots fingering the ssh server.
- Always use PKA.
- Disable password login.
- Disable root login.