OpenVPN Client/Server Implemenation
==== key signing ====
You can host the certificate authority on the vyos device itself. This is obviously not as secure as hosting it on a separate system. If someone was to get into the vyos they would have access to all your keys and would be able to sign new keys against the CA. Nonetheless, it is convenient and secure-enough for many sites. This is how it can be done.
From the VyOS, copy the easy-rsa directory into /config, where it won’t get lost on an upgrade.
cp -rv /usr/share/doc/openvpn/examples/easy-rsa/2.0/ /config/easy-rsa2 vi /config/easy-rsa2/vars
edit the options at the bottom of /config/easy-rsa2/vars to personalize them. Increasing KEY_SIZE to 2048 is recommended. Also, you can increase the certificate authority and key expiration. These are the defaults:
... # Increase this to 2048 if you # are paranoid. This will slow # down TLS negotiation performance # as well as the one-time DH parms # generation process. export KEY_SIZE=1024 # In how many days should the root CA key expire? export CA_EXPIRE=3650 # In how many days should certificates expire? export KEY_EXPIRE=3650 export KEY_COUNTRY="US" export KEY_PROVINCE="CA" export KEY_CITY="SanFrancisco" export KEY_ORG="Fort-Funston" export KEY_EMAIL="email@example.com"
now load the variables
$ cd /config/easy-rsa2/
$ source ./vars
start fresh in case there is something old lingering around in there. This will delete all keys, etc.
Build the certificate authority files
Build the diffie-hellman key exchange
Build the key for the server
$ ./build-key-server js-server
Copy the certs and keys into /config/auth
sudo cp /config/easy-rsa2/keys/ca.crt /config/auth/ sudo cp /config/easy-rsa2/keys/dh1024.pem /config/auth/ sudo cp /config/easy-rsa2/keys/js-server.key /config/auth/ sudo cp /config/easy-rsa2/keys/js-server.crt /config/auth/
Now you can build the key for the client and distribute to them
use ./build-key to generate a certificate that will connect to the vpn without a pass-phrase and ./build-key-pass if you want the user to enter a pass-phrase before connecting. ./build-key-pass is more secure in case someone steals your certificate and key they will still need to enter a password to connect.
$ ./build-key jimmy
answer all questions accordingly and be sure to answer yes to “Sign the certificate?” the “1 out of 1 certificate requests certified, commit?”
Now copy the keys and certs and create a config for Jimmy to remote in with. This is how I do it.
first make a directory for the client in /config/easy-rsa2/keys
cd /config/easy-rsa2/keys mkdir jimmy cp jimmy* jimmy/ cp ca.crt jimmy/
create a client config with your favorite text editor,
and add the following
client proto udp remote-cert-tls server verb 2 dev tun0 cert jimmy.crt key jimmy.key ca ca.crt remote [vpn-server host or ip] 1194
From your local computer download the config directory (jimmy) from the vpn server
$ scp -r firstname.lastname@example.org:/config/easy-rsa2/keys/jimmy .
this copies the jimmy directory into the current directory on your computer (the period designates current directory). If your on MS Windows you will need to use cygwin or putty-scp to do this. Also, if using MS Windows you will need to run unix2dos on those files
from your computer where you downloaded the jimmy folder to.
I wrote a script to do all this for you -> http://jasonschaefer.com/stuff/easyrsa-user-setup-vyos.sh.txt
Setting up the OpenVPN Server
The server subnet needs to be a different subnet from your LAN. Set it to something unique that will be unlikely on any remote networks your clients will be on.
The “–push route 10.101.101.0 255.255.255.0” needs to be changed to the subnet on the LAN of the router. The one you will VPN in to reach.
set interfaces openvpn vtun0 mode server set interfaces openvpn vtun0 server subnet 10.206.109.0/24 set interfaces openvpn vtun0 server name-server 10.101.101.1 set interfaces openvpn vtun0 server domain-name jasonschaefer.com set interfaces openvpn vtun0 server push-route 10.101.101.0/24 set service dns forwarding listen-on vtun0 set interfaces openvpn vtun0 tls cert-file /config/auth/js-server.crt set interfaces openvpn vtun0 tls key-file /config/auth/js-server.key set interfaces openvpn vtun0 tls ca-cert-file /config/auth/ca.crt set interfaces openvpn vtun0 tls dh-file /config/auth/dh1024.pem
#Set the firewall to allow openvpn through
set firewall name wan-local rule 40 action accept set firewall name wan-local rule 40 destination port openvpn set firewall name wan-local rule 40 protocol udp commit save
Thats it! Your done!
SITE TO SITE VPN
generate the passive key for head office from inside the easyrsa folder
source ./vars ./build-key-server site2site_server-passive scp keys/site2site_server-passive.* user@vpn-server-passive-host:/config/auth/
#active key for branch office, this side initiates the vpn handshakes
./build-key site2site_active scp keys/site2site_active.* user@vpn-server-active-host:/config/auth/
active site files in /config/auth/
passive site files in /config/auth/
#site to site openvpn
set interfaces openvpn vtun9 set interfaces openvpn vtun9 local-address 172.16.9.[1 | 2] set interfaces openvpn vtun9 remote-address 172.16.9.[1 | 2] set interfaces openvpn vtun9 remote-host [remote-vpn-host]
#standard openvpn port is 1194, best used for client/server mode. prevents ovpn config from needing port setting
set interfaces openvpn vtun9 local-port 1195 set interfaces openvpn vtun9 remote-port 1195 set interfaces openvpn vtun9 mode site-to-site set interfaces openvpn vtun9 tls ca-cert-file /root/ca.crt #the passive site cert/key needs to be signed as a server! set interfaces openvpn vtun9 tls key-file /root/[passive.key | active.key ] set interfaces openvpn vtun9 tls cert-file /root/[passive.crt | active.crt] set interfaces openvpn vtun9 tls role [active | passive] #dh1024.pem is required on passive host only! set interfaces openvpn vtun9 tls dh-file /root/dh1024.pem commit;save
#open firewall for openvpn
set firewall name wan-local rule 20 action accept set firewall name wan-local rule 20 destination port 1195 set firewall name wan-local rule 20 protocol tcp_udp
#set static routes to networks on other side of vpn, if any
set protocols static route 192.168.7.0/24 next-hop 172.16.9.[1 | 2] set protocols static route 192.168.8.0/24 next-hop 172.16.9.[1 | 2] commit;save
How to reach your vpn server and avoid using a static ip. We will be using afraid.org to automatically update a hostname’s A record with the public ip of your Vyos VPN server.
You will need to register for an account at https://freedns.afraid.org. Then create a subdomain, for this example it will be myvpnserver.mooo.com. Go to the “Dynamic DNS” section and copy the “Direct URL”.
Create a script under /config/scripts on your Vyos.
/usr/bin/curl -k [paste your direct url here]
Make it executable
chmod 755 /config/scripts/myvpnserver.mooo.com.sh
Now tell Vyos to run this with cron.
set system task-scheduler task dynamicDNS executable path /config/scripts/myvpnserver.mooo.com.sh
set system task-scheduler task dynamicDNS interval 15m
REVOKE KEYS ON VYOS
vyos@router:~$ cd /config/easy-rsa2/
vyos@router:/config/easy-rsa2$ ./revoke-full jimmy
Using configuration from /config/easy-rsa2/openssl.cnf Revoking Certificate 0E. Data Base Updated Using configuration from /config/easy-rsa2/openssl.cnf jimmy.crt: /C=US/ST=NM/L=SantaFe/O=Blah/CN=jimmy/emailAddressemail@example.com error 23 at 0 depth lookup:certificate revoked
The error 23 at 0 … is normal and expected.
Now copy the updated CRL (certificate revocation list) to /config/auth
vyos@router:/config/easy-rsa2$ cp keys/crl.pem /config/auth/
If this is the first revocation you need to add it to the config as well:
vyos@router# set interfaces openvpn vtun0 tls crl-file /config/auth/crl.pem
vyos@router# save; commit; exit
Saving configuration to ‘/config/config.boot’…
No configuration changes to commit
VERIFY REVOKED CERTIFICATES
You can verify the revoked keys with the openssl command
vyos@router:~$ openssl crl -in /config/auth/crl.pem -text
Revoked Certificates: Serial Number: 08 Revocation Date: Jan 30 00:19:24 2016 GMT Serial Number: 0E Revocation Date: Jul 13 22:51:50 2016 GMT
In the above example keys 08 and 0E have been revoked
vyos@router:~$ cat /config/easy-rsa2/keys/index.txt
V 230804225528Z 02 unknown /C=US/ST=NM/L=SantaFe/O=SITC/CN=jason/emailAddress=jason@local R 230806213443Z 160130001924Z 08 unknown /C=US/ST=NM/L=SantaFe/O=Blah/CN=john/emailAddress=john@localhost R 260711225142Z 160713225150Z 0E unknown /C=US/ST=NM/L=SantaFe/O=Blah/CN=jimmy/emailAddressfirstname.lastname@example.org
From this file index.txt, you can ascertain which serial numbers belong to which users!