Ssh Config Ssh Key

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  • Host dev HostName dev.example.com User john Port 2322. Ssh/targaryen.key LogLevel INFO Compression yes.
  • You must start ssh-agent (if it is not running already) before using ssh-add as follows: eval `ssh-agent -s` # start the agent ssh-add idrsa2 # Where idrsa2 is your new private key file. Note that the eval command starts the agent on Git Bash on Windows. Other environments may use a.

By setting a password, you could prevent unauthorized access to your servers and accounts if someone ever gets a hold of your private SSH key.

By default, the SSH client verifies the identity of the host to which it connects.

If the remote host key is unknown to your SSH client, you would be asked to accept it by typing “yes” or “no”.

This could cause a trouble when running from script that automatically connects to a remote host over SSH protocol.

Cool Tip: Slow SSH login? Password prompt takes too long? You can easily remove the delay! Read more →

This article explains how to bypass this verification step by disabling host key checking.

The Authenticity Of Host Can’t Be Established

When you log into a remote host that you have never connected before, the remote host key is most likely unknown to your SSH client, and you would be asked to confirm its fingerprint:

If your answer is ‘yes’, the SSH client continues login, and stores the host key locally in the file

Ssh Config Example

~/.ssh/known_hosts.

If your answer is ‘no’, the connection will be terminated.

If you would like to bypass this verification step, you can set the “StrictHostKeyChecking” option to “no” on the command line:

This option disables the prompt and automatically adds the host key to the ~/.ssh/known_hosts file.

Remote Host Identification Has Changed

However, even with “StrictHostKeyChecking=no“, you may be refused to connect with the following warning message:

If you are sure that it is harmless and the remote host key has been changed in a legitimate way, you can skip the host key checking by sending the key to a null known_hosts file:

You can also set these options permanently in ~/.ssh/config (for the current user) or in /etc/ssh/ssh_config (for all users).

Cool Tip: Log in to a remote Linux server without entering password! Set up password-less SSH login! Read more →

Also the option can be set either for the all hosts or for a given set of IP addresses.

Disable SSH host key checking for all hosts

Disable SSH host key checking For 192.168.0.0/24

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Ssh Config Password

This topic covers the Windows-specific configuration for OpenSSH Server (sshd).

Ssh Config Ssh Key

OpenSSH maintains detailed documentation for configuration options online at OpenSSH.com, which is not duplicated in this documentation set.

Configuring the default shell for OpenSSH in Windows

Ssh

Ssh Config Ssh Keys

The default command shell provides the experience a user sees when connecting to the server using SSH.The initial default Windows is the Windows Command shell (cmd.exe).Windows also includes PowerShell and Bash, and third party command shells are also available for Windows and may be configured as the default shell for a server.

To set the default command shell, first confirm that the OpenSSH installation folder is on the system path.For Windows, the default installation folder is SystemDrive:WindowsDirectorySystem32openssh.The following commands shows the current path setting, and add the default OpenSSH installation folder to it.

Command shellCommand to use
Commandpath
PowerShell$env:path

Configuring the default ssh shell is done in the Windows registry by adding the full path to the shell executable to ComputerHKEY_LOCAL_MACHINESOFTWAREOpenSSH in the string value DefaultShell.

As an example, the following Powershell command sets the default shell to be PowerShell.exe:

Windows Configurations in sshd_config

In Windows, sshd reads configuration data from %programdata%sshsshd_config by default, or a different configuration file may be specified by launching sshd.exe with the -f parameter.If the file is absent, sshd generates one with the default configuration when the service is started.

The elements listed below provide Windows-specific configuration possible through entries in sshd_config.There are other configuration settings possible in that are not listed here, as they are covered in detail in the online Win32 OpenSSH documentation.

AllowGroups, AllowUsers, DenyGroups, DenyUsers

Controlling which users and groups can connect to the server is done using the AllowGroups, AllowUsers, DenyGroups and DenyUsers directives.The allow/deny directives are processed in the following order: DenyUsers, AllowUsers, DenyGroups, and finally AllowGroups.All account names must be specified in lower case.See PATTERNS in ssh_config for more information on patterns for wildcards.

When configuring user/group based rules with a domain user or group, use the following format: user?domain*.Windows allows multiple of formats for specifying domain principals, but many conflict with standard Linux patterns.For that reason, * is added to cover FQDNs.Also, this approach uses '?', instead of @, to avoid conflicts with the username@host format.

Work group users/groups and internet-connected accounts are always resolved to their local account name (no domain part, similar to standard Unix names).Domain users and groups are strictly resolved to NameSamCompatible format - domain_short_nameuser_name.All user/group based configuration rules need to adhere to this format.

Examples for domain users and groups

Examples for local users and groups

AuthenticationMethods

For Windows OpenSSH, the only available authentication methods are 'password' and 'publickey'.

AuthorizedKeysFile

The default is '.ssh/authorized_keys .ssh/authorized_keys2'. If the path is not absolute, it is taken relative to user's home directory (or profile image path). Ex. c:usersuser. Note that if the user belongs to the administrator group, %programdata%/ssh/administrators_authorized_keys is used instead.

ChrootDirectory (Support added in v7.7.0.0)

This directive is only supported with sftp sessions. A remote session into cmd.exe wouldn't honor this. To setup a sftp-only chroot server, set ForceCommand to internal-sftp. You may also set up scp with chroot, by implementing a custom shell that would only allow scp and sftp.

HostKey

The defaults are %programdata%/ssh/ssh_host_ecdsa_key, %programdata%/ssh/ssh_host_ed25519_key, %programdata%/ssh/ssh_host_dsa_key, and %programdata%/ssh/ssh_host_rsa_key. If the defaults are not present, sshd automatically generates these on a service start.

Sshd_config Ssh Keys

Match

Note that pattern rules in this section. User and group names should be in lower case.

PermitRootLogin

Ssh

Not applicable in Windows. To prevent administrator login, use Administrators with DenyGroups directive.

SyslogFacility

If you need file based logging, use LOCAL0. Logs are generated under %programdata%sshlogs.For any other value, including the default value, AUTH directs logging to ETW. For more info, see Logging Facilities in Windows.

Not supported

Ssh Config Public Key

The following configuration options are not available in the OpenSSH version that ships in Windows Server 2019 and Windows 10 1809:

Ssh Install Ssh Key

  • AcceptEnv
  • AllowStreamLocalForwarding
  • AuthorizedKeysCommand
  • AuthorizedKeysCommandUser
  • AuthorizedPrincipalsCommand
  • AuthorizedPrincipalsCommandUser
  • Compression
  • ExposeAuthInfo
  • GSSAPIAuthentication
  • GSSAPICleanupCredentials
  • GSSAPIStrictAcceptorCheck
  • HostbasedAcceptedKeyTypes
  • HostbasedAuthentication
  • HostbasedUsesNameFromPacketOnly
  • IgnoreRhosts
  • IgnoreUserKnownHosts
  • KbdInteractiveAuthentication
  • KerberosAuthentication
  • KerberosGetAFSToken
  • KerberosOrLocalPasswd
  • KerberosTicketCleanup
  • PermitTunnel
  • PermitUserEnvironment
  • PermitUserRC
  • PidFile
  • PrintLastLog
  • RDomain
  • StreamLocalBindMask
  • StreamLocalBindUnlink
  • StrictModes
  • X11DisplayOffset
  • X11Forwarding
  • X11UseLocalhost
  • XAuthLocation