OpenConnect VPN Server with SAML authentication

OpenConnect VPN server is an SSL VPN server that is secure, small, fast and configurable. It implements the OpenConnect SSL VPN protocol and has also (currently experimental) compatibility with clients using the AnyConnect SSL VPN protocol. The OpenConnect protocol provides a dual TCP/UDP VPN channel and uses the standard IETF security protocols to secure it. While there is some recent movement towards SAML compatibility in an OpenConnect client, this SAML authentication module specifically emulates the behaviour of a Cisco Anyconnect headend for compatibility with Anyconnect clients. It is tested with version 4.8. It has not been tested with Openconnect.

Homepage Documentation Source

Docker Features

• Base: Alpine Latest
• Latest OpenConnect Server 1.0.0 + SAML support implemented by me, here
• SAML2 Authentication Support
• Size: 47.5MB
• Customizing the DNS servers used for queries over the VPN
• Supports tunneling all traffic over the VPN or tunneling only specific routes via split-include
• Create certs automatically using default or provided values, or drop your own certs in /config/certs

Run container from Docker registry

The container is available from the Docker registry and this is the simplest way to get it. It needs a fair few environment variables, so I suggest using docker-compose.

Quick Start

If you have not already done so, install docker-compose in accordance with its documentation.

In an empty directory, create a file called docker-compose.yaml and insert the below contents, substituting values suitable for your environment:

version: "3"

services:
  ocserv:
    container_name: ocserv
    image: morganonbass/ocserv-saml:latest
    ports:
      - "443:443/tcp"
      - "443:443/udp"
    environment:
      HOSTNAME: 'vpn.example.com'
      LISTEN_PORT: 443
      TUNNEL_MODE: 'split-include'
      TUNNEL_ROUTES: '192.168.1.0/24, 192.168.69.0/24'
      DNS_SERVERS: 192.168.1.1
      DEFAULT_DOMAIN: 'internal.example.com'
      SPLIT_DNS_DOMAINS: 'internal.example.com'
      CLIENTNET: 192.168.248.0
      CLIENTNETMASK: 255.255.255.128
    volumes:
      - './config/:/config/'
    cap_add:
      - NET_ADMIN
    privileged: true
    restart: unless-stopped

Then, create a directory called 'config' (or match your volume definition above if you differ from the example), and populate it with the following files:

File	Required	Details
idp-metadata.xml	Yes	Your SAML identity provider supplies this
idp-cert.pem	Yes	Your SAML identity provider supplies this
certs/server-cert.pem	No	Our certificate, for SSL/TLS and signing SAML communications if needed
certs/server-key.pem	No	Key for above. If not supplied, a self signed cert will be generated

Then, start the vpn service like so:

docker-compose up -d

On start, the docker entrypoint script will drop and populate the following using parameters supplied by docker-compose.yaml:

File	Can I edit this?	Details
ocserv.conf	Knock yourself out	Ocserv configuration file. This will be autogenerated with parameters supplied in docker-compose.yaml
sp-metadata.xml	Nope	Our SAML service provider metadata file. Don't edit this, it emulates ASA behaviour for Anyconnect compatibility
sso.conf	Maybe, but why?	Ocserv SAML module configuration file. Just tells it where to find its own metadata files and certs, not much needs editing here

Using your own certificates

On start, the server checks for the following files:

/config/certs/server-key.pem
/config/certs/server-cert.pem

If these do not exist, a self signed certificate will be created. You may of course place your own signed certificates at this location.

Advanced Configuration:

All of the relevant config files are in the /config volume. You may edit them to make use of more of Openconnect's features. Some advanced features include setting up site to site VPN links, User Groups, Proxy Protocol support and more.

Variables

Environment Variables

Variable	Required	Function	Example
HOSTNAME	Yes	Hostname, needed to construct SAML parameters	vpn.domain.com
LISTEN_PORT	No	Listening port for VPN connections	443
DNS_SERVERS	No	Comma delimited name servers	8.8.8.8,8.8.4.4
TUNNEL_MODE	No	Tunnel mode (all / split-include)	split-include
TUNNEL_ROUTES	No	Comma delimited tunnel routes in CIDR notation	192.168.1.0/24
DEFAULT_DOMAIN	No	Default domain to advertise to clients (DNS search scope)	internal.domain.com
SPLIT_DNS_DOMAINS	No	Comma delimited dns domains	internal.domain.com
CLIENTNET	No	Network from which to assign client IPs	192.168.255.0
CLIENTNETMASK	No	Client subnet mask	255.255.255.0

Volumes

Volume	Required	Function	Example
config	Yes	OpenConnect config files	/your/config/path/:/config

Ports

Port	Proto	Required	Function	Example
443	TCP	Yes	OpenConnect server TCP listening port	443:443
443	UDP	Yes	OpenConnect server UDP listening port	443:443/udp

Login and Logout Log Messages

After a user successfully logins to the VPN a message will be logged in the docker log.
Example of login message:

[info] User bob Connected - Server: 192.168.1.165 VPN IP: 192.168.255.194 Remote IP: 107.92.120.188 

Example of logoff message:

[info] User bob Disconnected - Bytes In: 175856 Bytes Out: 4746819 Duration:63

Issues

If you are having issues with this container please submit an issue on GitHub. Please provide logs, docker version and other information that can simplify reproducing the issue. Using the latest stable verison of Docker is always recommended. Support for older version is on a best-effort basis.