Préparation

Dans un premier temps, il faudra avoir une connexion à Internet, utiliser un serveur DNS et désactiver SELinux.

Pour ceux qui auraient manqué des étapes, les voici:

Assurez-vous d'avoir installé le dépôt EPEL car UCARP vient de cette source.

Une fois ces étapes effectuées, entrons dans le vif du sujet !

Installation

yum -y install openvpn easy-rsa

cp /usr/share/doc/openvpn-*/sample/sample-config-files/server.conf /etc/openvpn

vi /etc/openvpn/server.conf

push "redirect-gateway def1 bypass-dhcp"
push "dhcp-option DNS 8.8.8.8"
user nobody
group nobody

mkdir -p /etc/openvpn/easy-rsa/keys
cp -rf /usr/share/easy-rsa/2.0/* /etc/openvpn/easy-rsa

vi /etc/openvpn/easy-rsa/vars

export KEY_COUNTRY="FR"
export KEY_PROVINCE="Hearult"
export KEY_CITY="Juvignac"
export KEY_ORG="Tala Informatique"
export KEY_EMAIL="root@tala.informatique.fr"
export KEY_OU="Informatique"

cp /etc/openvpn/easy-rsa/openssl-1.0.0.cnf /etc/openvpn/easy-rsa/openssl.cnf

cd /etc/openvpn/easy-rsa
source ./vars
./clean-all
./build-ca

[root@openvpn easy-rsa]# ./build-key-server server
Generating a 2048 bit RSA private key
.............+++
.........+++
writing new private key to 'server.key'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [FR]:
State or Province Name (full name) [Herault]:
Locality Name (eg, city) [Juvignac]:
Organization Name (eg, company) [Tala Informatique]:
Organizational Unit Name (eg, section) [Informatique]:
Common Name (eg, your name or your server's hostname) [server]:
Name [EasyRSA]:
Email Address [root@tala.informatique.fr]:

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:
Using configuration from /etc/openvpn/easy-rsa/openssl-1.0.0.cnf
Check that the request matches the signature
Signature ok
The Subject's Distinguished Name is as follows
countryName           :PRINTABLE:'FR'
stateOrProvinceName   :PRINTABLE:'Herault'
localityName          :PRINTABLE:'Juvignac'
organizationName      :PRINTABLE:'Tala Informatique'
organizationalUnitName:PRINTABLE:'Informatique'
commonName            :PRINTABLE:'server'
name                  :PRINTABLE:'EasyRSA'
emailAddress          :IA5STRING:'root@tala.informatique.fr'
Certificate is to be certified until Oct 14 17:16:17 2025 GMT (3650 days)
Sign the certificate? [y/n]:y


1 out of 1 certificate requests certified, commit? [y/n]y
Write out database with 1 new entries
Data Base Updated

./build-dh
cd /etc/openvpn/easy-rsa/keys
cp dh2048.pem ca.crt server.crt server.key /etc/openvpn

cd /etc/openvpn/easy-rsa
./build-key client
Generating a 2048 bit RSA private key
...........+++
............+++
writing new private key to 'client.key'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [FR]:
State or Province Name (full name) [Herault]:
Locality Name (eg, city) [Juvignac]:
Organization Name (eg, company) [Tala Informatique]:
Organizational Unit Name (eg, section) [Informatique]:
Common Name (eg, your name or your server's hostname) [client]:
Name [EasyRSA]:
Email Address [root@tala.informatique.fr]:

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:
Using configuration from /etc/openvpn/easy-rsa/openssl-1.0.0.cnf
Check that the request matches the signature
Signature ok
The Subject's Distinguished Name is as follows
countryName           :PRINTABLE:'FR'
stateOrProvinceName   :PRINTABLE:'Herault'
localityName          :PRINTABLE:'Juvignac'
organizationName      :PRINTABLE:'Tala Informatique'
organizationalUnitName:PRINTABLE:'Informatique'
commonName            :PRINTABLE:'client'
name                  :PRINTABLE:'EasyRSA'
emailAddress          :IA5STRING:'root@tala.informatique.fr'
Certificate is to be certified until Oct 14 17:22:18 2025 GMT (3650 days)
Sign the certificate? [y/n]:y


1 out of 1 certificate requests certified, commit? [y/n]y
Write out database with 1 new entries
Data Base Updated

iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
iptables -F FORWARD
service iptables save
vi /etc/sysctl.conf
       net.ipv4.ip_forward = 1

service openvpn start
chkconfig openvpn on

Configuring OpenVPN Client