OpenConnect
OpenConnect-compatible server feature is available from this release. Openconnect VPN supports SSL connection and offers full network access. SSL VPN network extension connects the end-user system to the corporate network with access controls based only on network layer information, such as destination IP address and port number. So, it provides safe communication for all types of device traffic across public networks and private networks, also encrypts the traffic with SSL protocol.
The remote user will use the openconnect client to connect to the router and will receive an IP address from a VPN pool, allowing full access to the network.
Configuration
SSL Certificates
We need to generate the certificate which authenticates users who attempt to access the network resource through the SSL VPN tunnels. The following commands will create a self signed certificates and will be stored in configuration:
run generate pki ca install <CA name>
run generate pki certificate sign <CA name> install <Server name>
We can also create the certificates using Cerbort which is an easy-to-use client that fetches a certificate from Let’s Encrypt an open certificate authority launched by the EFF, Mozilla, and others and deploys it to a web server.
sudo certbot certonly --standalone --preferred-challenges http -d <domain name>
Server Configuration
set vpn openconnect authentication local-users username <user> password <pass>
set vpn openconnect authentication mode <local password|radius>
set vpn openconnect network-settings client-ip-settings subnet <subnet>
set vpn openconnect network-settings name-server <address>
set vpn openconnect network-settings name-server <address>
set vpn openconnect ssl ca-certificate <pki-ca-name>
set vpn openconnect ssl certificate <pki-cert-name>
set vpn openconnect ssl passphrase <pki-password>
2FA OTP support
Instead of password only authentication, 2FA password authentication + OTP key can be used. Alternatively, OTP authentication only, without a password, can be used. To do this, an OTP configuration must be added to the configuration above:
set vpn openconnect authentication mode local <password-otp|otp>
set vpn openconnect authentication local-users username <user> otp <key>
set vpn openconnect authentication local-users username <user> interval <interval (optional)>
set vpn openconnect authentication local-users username <user> otp-length <otp-length (optional)>
set vpn openconnect authentication local-users username <user> token-type <token-type (optional)>
For generating an OTP key in VyOS, you can use the CLI command (operational mode):
generate openconnect username <user> otp-key hotp-time
Verification
vyos@vyos:~$ sh openconnect-server sessions
interface username ip remote IP RX TX state uptime
----------- ---------- ------------- ----------- ------- --------- --------- --------
sslvpn0 tst 172.20.20.198 192.168.6.1 0 bytes 152 bytes connected 3s
Note
It is compatible with Cisco (R) AnyConnect (R) clients.
Example
SSL Certificates generation
Follow the instructions to generate CA cert (in configuration mode):
vyos@vyos# run generate pki ca install ca-ocserv
Enter private key type: [rsa, dsa, ec] (Default: rsa)
Enter private key bits: (Default: 2048)
Enter country code: (Default: GB) US
Enter state: (Default: Some-State) Delaware
Enter locality: (Default: Some-City) Mycity
Enter organization name: (Default: VyOS) MyORG
Enter common name: (Default: vyos.io) oc-ca
Enter how many days certificate will be valid: (Default: 1825) 3650
Note: If you plan to use the generated key on this router, do not encrypt the private key.
Do you want to encrypt the private key with a passphrase? [y/N] N
2 value(s) installed. Use "compare" to see the pending changes, and "commit" to apply.
[edit]
Follow the instructions to generate server cert (in configuration mode):
vyos@vyos# run generate pki certificate sign ca-ocserv install srv-ocserv
Do you already have a certificate request? [y/N] N
Enter private key type: [rsa, dsa, ec] (Default: rsa)
Enter private key bits: (Default: 2048)
Enter country code: (Default: GB) US
Enter state: (Default: Some-State) Delaware
Enter locality: (Default: Some-City) Mycity
Enter organization name: (Default: VyOS) MyORG
Enter common name: (Default: vyos.io) oc-srv
Do you want to configure Subject Alternative Names? [y/N] N
Enter how many days certificate will be valid: (Default: 365) 1830
Enter certificate type: (client, server) (Default: server)
Note: If you plan to use the generated key on this router, do not encrypt the private key.
Do you want to encrypt the private key with a passphrase? [y/N] N
2 value(s) installed. Use "compare" to see the pending changes, and "commit" to apply.
[edit]
Each of the install command should be applied to the configuration and commited before using under the openconnect configuration:
vyos@vyos# commit
[edit]
vyos@vyos# save
Saving configuration to '/config/config.boot'...
Done
[edit]
Openconnect Configuration
Simple setup with one user added and password authentication:
set vpn openconnect authentication local-users username tst password 'OC_bad_Secret'
set vpn openconnect authentication mode local password
set vpn openconnect network-settings client-ip-settings subnet '172.20.20.0/24'
set vpn openconnect network-settings name-server '10.1.1.1'
set vpn openconnect network-settings name-server '10.1.1.2'
set vpn openconnect ssl ca-certificate 'ca-ocserv'
set vpn openconnect ssl certificate 'srv-ocserv'
To enable the HTTP security headers in the configuration file, use the command:
set vpn openconnect http-security-headers
Adding a 2FA with an OTP-key
First the OTP keys must be generated and sent to the user and to the configuration:
vyos@vyos:~$ generate openconnect username tst otp-key hotp-time
# You can share it with the user, he just needs to scan the QR in his OTP app
# username: tst
# OTP KEY: 5PA4SGYTQSGOBO3H3EQSSNCUNZAYAPH2
# OTP URL: otpauth://totp/tst@vyos?secret=5PA4SGYTQSGOBO3H3EQSSNCUNZAYAPH2&digits=6&period=30
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# To add this OTP key to configuration, run the following commands:
set vpn openconnect authentication local-users username tst otp key 'ebc1c91b13848ce0bb67d9212934546e41803cfa'
Next it is necessary to configure 2FA for OpenConnect:
set vpn openconnect authentication mode local password-otp
set vpn openconnect authentication local-users username tst otp key 'ebc1c91b13848ce0bb67d9212934546e41803cfa'
Now when connecting the user will first be asked for the password and then the OTP key.
Warning
When using Time-based one-time password (TOTP) (OTP HOTP-time), be sure that the time on the server and the OTP token generator are synchronized by NTP
To display the configured OTP user settings, use the command:
show openconnect-server user <username> otp <full|key-b32|key-hex|qrcode|uri>
Identity Based Configuration
OpenConnect supports a subset of it’s configuration options to be applied on a per user/group basis, for configuration purposes we refer to this functionality as “Identity based config”. The following OpenConnect Server Manual outlines the set of configuration options that are allowed. This can be leveraged to apply different sets of configs to different users or groups of users.
sudo mkdir -p /config/auth/ocserv/config-per-user
sudo touch /config/auth/ocserv/default-user.conf
set vpn set vpn openconnect authentication identity-based-config mode user
set vpn openconnect authentication identity-based-config directory /config/auth/ocserv/config-per-user
set vpn openconnect authentication identity-based-config default-config /config/auth/ocserv/default-user.conf
Warning
The above directory and default-config must be a child directory of /config/auth, since files outside this directory are not persisted after an image upgrade.
Once you commit the above changes you can create a config file in the /config/auth/ocserv/config-per-user directory that matches a username of a user you have created e.g. “tst”. Now when logging in with the “tst” user the config options you set in this file will be loaded.
Be sure to set a sane default config in the default config file, this will be loaded in the case that a user is authenticated and no file is found in the configured directory matching the users username/group.
sudo nano /config/auth/ocserv/config-per-user/tst
The same configuration options apply when Identity based config is configured in group mode except that group mode can only be used with RADIUS authentication.
Warning
OpenConnect server matches the filename in a case sensitive manner, make sure the username/group name you configure matches the filename exactly.
Configuring RADIUS accounting
OpenConnect can be configured to send accounting information to a RADIUS server to capture user session data such as time of connect/disconnect, data transferred, and so on.
Configure an accounting server and enable accounting with:
set vpn openconnect accounting mode radius
set vpn openconnect accounting radius server 172.20.20.10
set vpn openconnect accounting radius server 172.20.20.10 port 1813
set vpn openconnect accounting radius server 172.20.20.10 key your_radius_secret
Warning
The RADIUS accounting feature must be used with the OpenConnect authentication mode RADIUS. It cannot be used with local authentication. You must configure the OpenConnect authentication mode to “radius”.
An example of the data captured by a FREERADIUS server with sql accounting:
mysql> SELECT username, nasipaddress, acctstarttime, acctstoptime, acctinputoctets, acctoutputoctets, callingstationid, framedipaddress, connectinfo_start FROM radacct;
+----------+---------------+---------------------+---------------------+-----------------+------------------+-------------------+-----------------+-----------------------------------+
| username | nasipaddress | acctstarttime | acctstoptime | acctinputoctets | acctoutputoctets | callingstationid | framedipaddress | connectinfo_start |
+----------+---------------+---------------------+---------------------+-----------------+------------------+-------------------+-----------------+-----------------------------------+
| test | 198.51.100.15 | 2023-01-13 00:59:15 | 2023-01-13 00:59:21 | 10606 | 152 | 192.168.6.1 | 172.20.20.198 | Open AnyConnect VPN Agent v8.05-1 |
+----------+---------------+---------------------+---------------------+-----------------+------------------+-------------------+-----------------+-----------------------------------+