OpenVPN configuration for server and multiple clients

This is a simple post showing a basic configuration for setting up OpenVPN server accepting multiple clients with TLS.

First of all generate self-signed server and client private key and certificates, and dh params. Make sure to write the Organization Name AND Common Name (CN) when asked, otherwise openvpn will fail to verify the certificates.

openssl req -newkey rsa:2048 -nodes -keyout serverkey.pem -x509 -days 365000 -out servercert.pem
openssl req -newkey rsa:2048 -nodes -keyout clientkey.pem -out client.csr
openssl x509 -req -days 365000 -in client.csr -CA servercert.pem -CAkey serverkey.pem -set_serial 01 -out clientcert.pem
openssl dhparam -outform PEM -out dh.pem 1024


Server configuration:

dev tun
mode server
tls-server
server 10.8.0.0 255.255.255.0
ca servercert.pem
cert servercert.pem
key serverkey.pem
dh dh.pem
duplicate-cn
topology subnet
keepalive 10 60
ping-timer-rem
persist-tun
persist-key


If you plan to use the server as gateway like configured below, don't forget to enable IP forwarding and masquerading:

sysctl net.ipv4.ip_forward=1
iptables -t nat -A POSTROUTING -s 10.8.0.0/24 -j MASQUERADE

Client configuration:

client
redirect-gateway
tls-client
key clientkey.pem
cert clientcert.pem
ca servercert.pem
keepalive 10 60
dev tun


Have fun, tune as needed.

Switch window by name on Linux - alternative to Alt+Tab

Today I want to share a very simple script that works with most Linux window managers: switch window by name.
It works like this: you press Ctrl+Alt+M, then a dialog appears where you write part of the name of the window, and you'll get switched to the window that matches the provided name.The string your provide will match part of window names in case-insensitive mode.
That means if you have "Foo - Mozilla Firefox" and type in "fire" you'll switch to firefox.

Note: it probably doesn't work with your configuration of awesome wm due to weird focus management.

The first step is to install the necessary packages:

apt-get install xbindkeys wmctrl zenity

With wmctrl we're able to switch to a window by specifying the name, while with xbindkeys we can bind Ctrl+Alt+M to open a zenity dialog then call wmctrl with the provided window name.

The only thing you need is the following file somewhere, let's call it keys.rc:

"WINDOWID='' app=$(zenity --text "App" --title "App" --entry) && wmctrl -R $app"
  control+alt + m

Now run xbindkeys -f keys.rc and we're done! Press Ctrl+Alt+M then type in the name of the window you want to switch to.

We can also add simpler bindings like this:

"wmctrl -R Firefox"
  control+alt + f

Now pressing Ctrl+Alt+F will switch to a firefox window.

Note that if it matches more window, only one of the window will be chosen obviously. The choice depends on xbindkeys.

I'm not using Alt+Tab anymore.