Linux OpenVPN server and Windows client simple Howto

# apt-get install openvpn
# cd /usr/share/doc/openvpn/examples/easy-rsa
# . ./vars
# ./clean-all
# ./build-ca // generates ca.crt, ca.key
# ./build-key-server diana // generates 01.pem, diana.crt, diana.csr, diana.key
# ./build-key vesta // generates vesta.crt, vesta.csr, vesta.key
# ./build-dh
# openvpn --genkey --secret ta.key

SERVER
copy files just generated to /etc/openvpn

# vim /etc/openvpn/server.conf

local 192.168.1.100
port 1194
proto tcp // i can't run under UDP
dev tun
tls-server
ca ca.crt
cert diana.crt
key diana.key
tls-auth ta.key 0
dh dh1024.pem
server 10.12.0.0 255.255.255.0
ifconfig-pool-persist ipp.txt
push "redirect-gateway"
push "dhcp-option DNS 10.12.0.1"
push "dhcp-option DNS 140.117.205.1"
push "dhcp-option DNS 140.117.11.1"
keepalive 10 120
comp-lzo
max-clients 3
persist-key
persist-tun
status /var/log/openvpn-status.log
verb 3
daemon

# /etc/init.d/openvpn start
# sysctl -w net.ipv4.ip_forward=1
# iptables -t nat -A POSTROUTING -s 10.12.0.0/24 -o eth0 -j MASQUERADE

CLIENT
to http://openvpn.se/ to get OpenVPN Windows GUI, and install it.
copy client.ovpn from Program $OVPNInstDir/sample-config to $OVPNInstDir/config.
copy ca.crt, ca.key, vesta.crt, vesta.csr, vesta.key to client_server to $OVPNInstDir/config.
modify client.ovpn

client
dev tun
proto tcp
remote 192.168.1.100 1194
resolv-retry infinite
nobind
persist-key
persist-tun
ns-cert-type server
tls-client
ca ca.crt
cert vesta.crt
key vesta.key
tls-auth ta.key 1
comp-lzo
verb 3

done