Login/User Management

The default VyOS user account (vyos), as well as newly created user accounts, have all capabilities to configure the system. All accounts have sudo capabilities and therefore can operate as root on the system.

Both local administered and remote administered RADIUS accounts are supported.

Local

set system login user <name> full-name “<string>”

Create new system user with username <name> and real-name specified by <string>.

set system login user <name> authentication plaintext-password <password>

Specify the plaintext password user by user <name> on this system. The plaintext password will be automatically transferred into a secure hashed password and not saved anywhere in plaintext.

set system login user <name> authentication encrypted-password <password>

Setup encrypted password for given username. This is useful for transferring a hashed password from system to system.

set system login user <name> disable

Disable (lock) account. User will not be able to log in.

Key Based Authentication

It is highly recommended to use SSH key authentication. By default there is only one user (vyos), and you can assign any number of keys to that user. You can generate a ssh key with the ssh-keygen command on your local machine, which will (by default) save it as ~/.ssh/id_rsa.pub.

Every SSH key comes in three parts:

ssh-rsa AAAAB3NzaC1yc2EAAAABAA...VBD5lKwEWB username@host.example.com

Only the type (ssh-rsa) and the key (AAAB3N...) are used. Note that the key will usually be several hundred characters long, and you will need to copy and paste it. Some terminal emulators may accidentally split this over several lines. Be attentive when you paste it that it only pastes as a single line. The third part is simply an identifier, and is for your own reference.

See also

SSH Operation

set system login user <username> authentication public-keys <identifier> key <key>

Assign the SSH public key portion <key> identified by per-key <identifier> to the local user <username>.

set system login user <username> authentication public-keys <identifier> type <type>

Every SSH public key portion referenced by <identifier> requires the configuration of the <type> of public-key used. This type can be any of:

• ecdsa-sha2-nistp256

• ecdsa-sha2-nistp384

• ecdsa-sha2-nistp521

• ssh-dss

• ssh-ed25519

• ssh-rsa

Note

You can assign multiple keys to the same user by using a unique identifier per SSH key.

set system login user <username> authentication public-keys <identifier> options <options>

Set the options for this public key. See the ssh authorized_keys man page for details of what you can specify here. To place a " character in the options field, use ", for example from="10.0.0.0/24" to restrict where the user may connect from when using this key.

MFA/2FA authentication using OTP (one time passwords)

It is possible to enhance authentication security by using the 2FA/MFA feature together with OTP on VyOS. 2FA/MFA is configured independently per each user. If an OTP key is configured for a user, 2FA/MFA is automatically enabled for that particular user. If a user does not have an OTP key configured, there is no 2FA/MFA check for that user.

set system login user <username> authentication otp key <key>

Enable OTP 2FA for user username with default settings, using the BASE32 encoded 2FA/MFA key specified by <key>.

Optional/default settings

set system login user <username> authentication otp rate-limit <limit>

default: 3

Limit logins to <limit> per every rate-time seconds. Rate limit must be between 1 and 10 attempts.

set system login user <username> authentication otp rate-time <seconds>

default: 30

Limit logins to rate-limit attemps per every <seconds>. Rate time must be between 15 and 600 seconds.

set system login user <username> authentication otp window-size <size>

default: 3

Set window of concurrently valid codes.

By default, a new token is generated every 30 seconds by the mobile application. In order to compensate for possible time-skew between the client and the server, an extra token before and after the current time is allowed. This allows for a time skew of up to 30 seconds between authentication server and client.

For example, if problems with poor time synchronization are experienced, the window can be increased from its default size of 3 permitted codes (one previous code, the current code, the next code) to 17 permitted codes (the 8 previous codes, the current code, and the 8 next codes). This will permit for a time skew of up to 4 minutes between client and server.

The window size must be between 1 and 21.

OTP-key generation

The following command can be used to generate the OTP key as well as the CLI commands to configure them:

generate system login username <username> otp-key hotp-time rate-limit <1-10> rate-time <15-600> window-size <1-21>

An example of key generation:

vyos@vyos:~$ generate system login username otptester otp-key hotp-time rate-limit 2 rate-time 20 window-size 5
# You can share it with the user, he just needs to scan the QR in his OTP app
# username:  otptester
# OTP KEY:  J5A64ERPMGJOZXY6FMHHLKXKANNI6TCY
# OTP URL:  otpauth://totp/otptester@vyos?secret=J5A64ERPMGJOZXY6FMHHLKXKANNI6TCY&digits=6&period=30
█████████████████████████████████████████████
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# To add this OTP key to configuration, run the following commands:
set system login user otptester authentication otp key 'J5A64ERPMGJOZXY6FMHHLKXKANNI6TCY'
set system login user otptester authentication otp rate-limit '2'
set system login user otptester authentication otp rate-time '20'
set system login user otptester authentication otp window-size '5'

Display OTP key for user

To display the configured OTP user key, use the command:

sh system login authentication user <username> otp <full|key-b32|qrcode|uri>

An example:

vyos@vyos:~$ sh system login authentication user otptester otp full
# You can share it with the user, he just needs to scan the QR in his OTP app
# username: otptester
# OTP KEY: J5A64ERPMGJOZXY6FMHHLKXKANNI6TCY
# OTP URL: otpauth://totp/otptester@vyos?secret=J5A64ERPMGJOZXY6FMHHLKXKANNI6TCY&digits=6&period=30
█████████████████████████████████████████████
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# To add this OTP key to configuration, run the following commands:
set system login user otptester authentication otp key 'J5A64ERPMGJOZXY6FMHHLKXKANNI6TCY'
set system login user otptester authentication otp rate-limit '2'
set system login user otptester authentication otp rate-time '20'
set system login user otptester authentication otp window-size '5'

Once a user has 2FA/OTP configured against their account, they must login using their password with the OTP code appended to it. For example: If the users password is vyosrocks and the OTP code is 817454 then they would enter their password as vyosrocks817454

RADIUS

In large deployments it is not reasonable to configure each user individually on every system. VyOS supports using RADIUS servers as backend for user authentication.

Configuration

set system login radius server <address> key <secret>

Specify the IP <address> of the RADIUS server user with the pre-shared-secret given in <secret>.

Multiple servers can be specified.

set system login radius server <address> port <port>

Configure the discrete port under which the RADIUS server can be reached.

This defaults to 1812.

set system login radius server <address> disable

Temporary disable this RADIUS server. It won’t be queried.

set system login radius server <address> timeout <timeout>

Setup the <timeout> in seconds when querying the RADIUS server.

set system login radius source-address <address>

RADIUS servers could be hardened by only allowing certain IP addresses to connect. As of this the source address of each RADIUS query can be configured.

If unset, incoming connections to the RADIUS server will use the nearest interface address pointing towards the server - making it error prone on e.g. OSPF networks when a link fails and a backup route is taken.

set system login radius vrf <name>

Source all connections to the RADIUS servers from given VRF <name>.

Hint

If you want to have admin users to authenticate via RADIUS it is essential to sent the Cisco-AV-Pair shell:priv-lvl=15 attribute. Without the attribute you will only get regular, non privilegued, system users.

TACACS+

In addition to RADIUS, TACACS can also be found in large deployments. VyOS only supports Authentication via TACACS+ servers but does not support Authorization or Accounting yet

TACACS is defined in RFC 8907.

Configuration

set system login tacas server <address> key <secret>

Specify the IP <address> of the TACACS server user with the pre-shared-secret given in <secret>.

Multiple servers can be specified.

set system login tacas server <address> port <port>

Configure the discrete port under which the TACACS server can be reached.

This defaults to 49.

set system login tacas server <address> disable

Temporary disable this TACACS server. It won’t be queried.

set system login tacas server <address> timeout <timeout>

Setup the <timeout> in seconds when querying the TACACS server.

set system login tacas source-address <address>

TACACS servers could be hardened by only allowing certain IP addresses to connect. As of this the source address of each TACACS query can be configured.

If unset, incoming connections to the TACACS server will use the nearest interface address pointing towards the server - making it error prone on e.g. OSPF networks when a link fails and a backup route is taken.

set system login tacas vrf <name>

Source all connections to the TACACS servers from given VRF <name>.

Login Banner

You are able to set post-login or pre-login banner messages to display certain information for this system.

set system login banner pre-login <message>

Configure <message> which is shown during SSH connect and before a user is logged in.

set system login banner post-login <message>

Configure <message> which is shown after user has logged in to the system.

Note

To create a new line in your login message you need to escape the new line character by using \\n.

Limits

Login limits

set system login max-login-session <number>

Set a limit on the maximum number of concurrent logged-in users on the system.

This option must be used with timeout option.

set system login timeout <timeout>

Configure session timeout after which the user will be logged out.

Example

In the following example, both User1 and User2 will be able to SSH into VyOS as user vyos using their very own keys. User1 is restricted to only be able to connect from a single IP address. In addition if password base login is wanted for the vyos user a 2FA/MFA keycode is required in addition to the password.

set system login user vyos authentication public-keys 'User1' key "AAAAB3Nz...KwEW"
set system login user vyos authentication public-keys 'User1' type ssh-rsa
set system login user vyos authentication public-keys 'User1' options "from="192.168.0.100""

set system login user vyos authentication public-keys 'User2' key "AAAAQ39x...fbV3"
set system login user vyos authentication public-keys 'User2' type ssh-rsa

set system login user vyos authentication otp key OHZ3OJ7U2N25BK4G7SOFFJTZDTCFUUE2
set system login user vyos authentication plaintext-password vyos

TACACS Example

We use a vontainer providing the TACACS serve rin this example.

Load the container image in op-mode.

add container image lfkeitel/tacacs_plus:latest

set container network tac-test prefix '100.64.0.0/24'

set container name tacacs1 image 'lfkeitel/tacacs_plus:latest'
set container name tacacs1 network tac-test address '100.64.0.11'

set container name tacacs2 image 'lfkeitel/tacacs_plus:latest'
set container name tacacs2 network tac-test address '100.64.0.12'

set system login tacacs server 100.64.0.11 key 'tac_plus_key'
set system login tacacs server 100.64.0.12 key 'tac_plus_key'

commit

You can now SSH into your system using admin/admin as a default user supplied from the lfkeitel/tacacs_plus:latest container.