Encode and Decoder QR Code in Command Line

You can encode and decode QR code in command line by using ZXing.

Download jar file of zxing
http://repo1.maven.org/maven2/com/google/zxing/core/3.1.0/core-3.1.0.jar
http://repo1.maven.org/maven2/com/google/zxing/javase/3.1.0/javase-3.1.0.jar

Decoder QR code with an image file (img.png)
java -cp "core-3.1.0.jar:javase-3.1.0.jar" com.google.zxing.client.j2se.CommandLineRunner img.png

Encode QR code
java -cp "core-3.1.0.jar;javase-3.1.0.jar" com.google.zxing.client.j2se.CommandLineEncoder --image_format=GIF --output=output.gif "YHChien: Text for encode here"

Windows and Linux Spoof MAC Address

Linux
    ifconfig eth0 hw ether 00:11:22:33:44:55

Windows 

Registry
[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4D36E972-E325-11CE-BFC1-08002bE10318}\0008]

"NetworkAddress"="001122334455"
or GUI
Start/Settings/Network Connections/Local Area Connection
Properties/Configure ...

Advanced




Advanced (Another example)

OpenVPN

Server (IP 1.2.3.4, VPN Subnet 10.8.0.0 / 255.255.255.0)

Install OpenVPN

yum install openvpn

Generate Certificates (by using easy-rsa)

cd /usr/share/openvpn/easy-rsa/2.0/

#Setup parameters for certificate key generation

vi vars

source ./vars

#Clean all generated certificates and keys

./clean-all

#Generate server certificate

./build-ca

#Generate server key

./build-key-sever server

#Generate client key

./build-key client1

#Generate Diffie Hellman parameters

./build-dh

#Copy keys and certificates to openvpn conf folder (*crt: certificates; *key: private keys)

cd keys
cp -a ca.crt server.crt server.key dh1024.pem /etc/openvpn/

Create configuration

#copy sampel conf file to openvpn conf folder

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

#Edit conf file

vi /etc/openvpn/server.conf

#Server IP

local 1.2.3.4

#Listen port

port 1194

#protocol tcp or udp (default)

proto tcp

#tunnel tun (default) or tap

dev tun

#SSL/TLS Certificate

ca ca.crt

#Certificate

cert server.crt

#Private key

key server.key

#Diffie hellman

dh dh1024.pem

#VPN subnet, comment out for bridge mode

server 10.8.0.0 255.255.255.0

#Persistent assignment and log filename

ifconfig-pool-persist ipp.txt

#bridge mode(10.8.0.4/255.25.255.0: ip and nm of bridge interface; ip pool 10.8.0.50 ~ 10.8.0.100)

;server-bridge 10.8.0.4 255.255.255.0 10.8.0.50 10.8.0.100

#DHCP-proxy (use Server-side DHCP server to assign client IP)

;server-bridge

#enable compression

comp-lzo

#Maximum number of concurrently connected clients

;max-clients 100

#Server status

status openvpn-status.log

#Log

log-append

#verbosity

verb 3

#Start OpenVPN Service

service openvpn@server.service

Client

#Download ca.crt, client.crt, client.key from Server

cp -a ca.crt client1.crt client.key MyClient

#Copy sample client conf to folder

cp -a /usr/share/doc/openvpn-x.x.x/sample-config-files/client.conf MyClient

#Modify client conf (Linux) / ovpn file (windows)

#

vi client.conf

dev tun

proto tcp

remote 1.2.3.4 1194

ca ca.crt

cert client1.crt

key client1.key

#Execute client with .conf file

openvpn xxx.conf

#Execute client with .ovpn file

<Right-click ovpn file and select “Start OpenVPN on this config file” in Windows>

Windows Automatic Login

Run the following command

control userpasswords2

Uncheck "Users must enter a user name and password to use this computer."

Click OK and follow the dialog !