Tested only on a netgate SG-4860-1U

1. Install mandadory packages

   apt-get update
   apt-get install openvpn openssl curl jq vim --no-install-recommends 

2. Debian jessie (8) and stretch (9) repository have an old easy-rsa version (2.2) and we need at least 3.0.4, so we use github release.

wget --no-check-certificate https://github.com/OpenVPN/easy-rsa/releases/download/v3.0.4/EasyRSA-3.0.4.tgz
tar -xvzf EasyRSA-3.0.4.tgz
rm EasyRSA-3.0.4.tgz
mv EasyRSA-3.0.4/ /etc/openvpn/easy-rsa/

1. Generate a 2048 RSA public and private key for centrale, with server5 (use sub ca), and add them in

   vim /etc/openvpn/server/port_number.key
   vim /etc/openvpn/server/port_number.crt
   chmod 660 port_number.key port_number.crt #both files must belong to root:root

2. Generate diffie hellman file

   openssl dhparam -out /etc/openvpn/server/dh.pem 2048

3. Generate additonal key for tls-auth mode

   openvpn --genkey --secret /etc/openvpn/server/ta.key

4. Add root ca and sub ca in ca.crt file (root ca first!)

   vim /etc/openvpn/server/ca.crt

5. Add openvpn server configuration file (the file is normally stored in git)

   cp /home/acdsn/git/fw-rules/port_number/server.conf

6. Edit init.d file, replace *.conf (3 occurences) by server.conf and launch openvnp

   vim /etc/init.d/openvpn
   systemctl daemon-reload
   /etc/init.d/openvpn start #check with ps -Af | grep openvpn

7. Add file for CRL download

   touch /etc/openvpn/server/ca_crl.pem
   chmod 666 ca_crl.pem

8. Add client directories (as acdsn)

   mkdir /etc/acdsn/conf.d/client
   mkdir /etc/acdsn/conf.d/spool/client

9. If necessary, generate a organisation token with easygateway-web
10. Edit acdsn crontab and add (git pull of easygateway-scripts is maybe necessary):

    @daily /usr/bin/curl https://www.easygateway.co/ca_crl.pem -o /etc/openvpn/server/ca_crl.pem 
    */5 * * * * /bin/bash /home/acdsn/git/easygateway-scripts/minicentral/sync_eG/sync.sh -t 30 -p ORG_TOKEN -mCc

11. Update fw-rules and pull the new configuration.
    1. create a new interface
    2. create a new network (by default, use 192.168.60.0
    3. add the new network in rules 1 and 6)
    4. add masquerade in epilog

       #iptables -t nat -A POSTROUTING -o lan1 -j MASQUERADE
       #iptables -t nat -A POSTROUTING -o lan2 -j MASQUERADE
       #iptables -t nat -A POSTROUTING -o lan3 -j MASQUERADE
       #iptables -t nat -A POSTROUTING -o lan4 -j MASQUERADE
       #iptables -t nat -A POSTROUTING -o lan5 -j MASQUERADE

    5. git pull
    6. Uncomment lan specified in epilog, when vpn is necessary
    7. reload

       /home/acdsn/git/fw-rules/port_number/port_number.fw reload

12. Make a try!
    1. get config file from easygateway-web
    2. connect to centrale with tunnelblick
    3. try ping or vnc over vpn
13. Monit openvpn?