Post Script for OpenVPN clients

OpenVPN Logo
Image source: openvpn.net

Did you ever wanted to automatically do something after you OpenVPN client has successful connected to your OpenVPN server? To do so you can just add 2 simple lines to your client OpenVPN file:

script-security 2
up postscript.sh

This 2 lines above are doing the following:

  • script-security 2: Allows the calling of built-in executables (ip, route, ifconfig, …) and user-defined scripts (see next line). A script-security of 1 would mean that only built-in executables are allowed to be called.
  • up postscript.sh: This line defines the script which should be started after the client successfully connected to the server. In this case the script is called postscript.sh. If you don’t define the total path to the script here, the script has to be in the same directory as the OpenVPN client configuration.

And that’s it. After you are connected to your OpenVPN Server the given script will be fired up. Don’t forget to make the script executable for course.
For e.g. I use this to create a route on specific clients after they connected to the OpenVPN server. Of course you can do whatever you want inside the script.

How To get your Realtek RTL8111/RTL8168 working (updated guide)

Realtek Logo
Image Source: wikipedia.org

A lot of people will remember my guide how to get a RTL8111/RTL8168 running under your Linux box. This guide is almost 5 years old now and I wanted to make a complete overhaul, because a lot of things has changed since then.

Why do I need this driver anyway?

Some people asked me, “Why do I need this driver anyway? Doesn’t the Linux Kernel ship it?”. This is of course a valid question. As far as I can see this, the RTL8111/RTL8168 is not Open Source and this would be of course the reason why the driver isn’t included into the Linux Kernel. As long as the driver isn’t Open Sourced, we have to build it on our own.

The installation methods

A lot of things have changed since I written the initial article about how to compile the driver under Ubuntu / Debian. Today we can use 2 methods for installing the driver. The following lines describes both of them.

The automatic way

NOTE: Thanks to the user “Liyu” who gave me this hint!
NOTE2: For this way you need a working internet connection. You could use WLAN or a USB ethernet card like this one to get a temporary internet connection. You could also download every needed single package onto USB from another PC and install them in the right order.

As I said ealier, 5 years is a long time. And today Ubuntu and Debian have the driver included in it’s repository. For Debian you have to enable the non-free package sources. For Ubuntu you have to enable the universe package sources. You can easily do this by open your /etc/apt/sources.list as root with your editor of choice and add for each line starting with “deb” non-free or universe at the end. So for example, if you use Debian a line like:

deb http://ftp.de.debian.org/debian/ jessie main contrib

would become to

deb http://ftp.de.debian.org/debian/ jessie main contrib non-free

The same for Ubuntu:

deb http://de.archive.ubuntu.com/ubuntu/ xenial main restricted

would become to

deb http://de.archive.ubuntu.com/ubuntu/ xenial main restricted universe

After this you have to do a:

sudo apt-get update

You can of course use graphical ways to enable non-free or universe. After you enabled the missing package repository, you will be ready to install the driver. This can be easily done with the following command:

sudo apt-get install r8168-dkms

The procedure will take some time, depending on your CPU because the driver will be build for your working Kernel. The good side is, that if any Kernel update happens on your machine, the kernel will be rebuild against the new Kernel automatically after the update because of the use of dkms.
After the procedure is finished, you should be able to use your network card instantly. If not, you should consider a reboot of your PC then.

The manual way

Well, the manual way is almost the same as it was before in the initial article. Anyway, I want to rewrite the steps here again. This is also tested against newer Kernels ( >= 4.0) which caused a lot of trouble for some people in the past.

  • 1. Install dependencies: Once more you need a working internet connection for this. You could also use the Debian or Ubuntu DVD which includes the needed packages. To install the dependencies just enter the following command:
    sudo apt-get install build-essentials
  • 2. Download the driver: You can download the driver from the official Realtek homepage. This is the link: click me. From the table, select the “LINUX driver for kernel 3.x and 2.6.x and 2.4.x” for download.
  • 3. Blacklisting the r8169 driver: The r8169 is loaded when the r8168 is not found on your system. This will give you a network and internet connection, but with the r8169 driver your RTL8168 card will be very unstable. This means slow download rates, homepages taking hours to load and so on. To avoid that the r8169 is loaded, we blacklist it. This is be done by entering the following command:
    user@linux:~$ sudo sh -c 'echo blacklist r8169 >> /etc/modprobe.d/blacklist.conf'
  • 4. Untar the archive: After you successfully downloaded the driver, cd into the directory where the driver is downloaded and untar the driver with the following command:
    user@linux:~$ tar xfvj 0005-r8168-8.042.00.tar.bz2

    NOTE: Your tar filename can of course differs if you download a newer version in the future for e.g.

  • 5. Compiling and installing the driver: Now we have to start compiling the driver. For this you cd into the extracted directory:
    user@linux:~$ cd r8168-8.042.00

    NOTE: Don’t forget to change your version number in the future here.
    Now that you are in the right directory, we can start with the real compiling process. For this Realtek brings an easy to use script which is called autorun.sh. So, to start compiling and installing the driver enter:

    user@linux:~/r8168-8.042.000$ sudo ./autorun.sh

    You should see a output which looks like this:

    Check old driver and unload it.
    rmmod r8168
    Build the module and install
    At main.c:222:
    - SSL error:02001002:system library:fopen:No such file or directory: bss_file.c:175
    - SSL error:2006D080:BIO routines:BIO_new_file:no such file: bss_file.c:178
    sign-file: certs/signing_key.pem: No such file or directory
    Backup r8169.ko
    rename r8169.ko to r8169.bak
    DEPMOD 4.4.0-31-generic
    load module r8168
    Updating initramfs. Please wait.
    update-initramfs: Generating /boot/initrd.img-4.4.0-31-generic
    Completed.

    You can ignore the SSL error for now. The driver should be successfully compiled and installed into your system. The driver is already loaded and should work.

  • 6. Check the driver: As a final step, you could start checking if the driver is really loaded into your Kernel. For this you can use the command lsmod. lsmod lists all drivers, which are usable by your Kernel. So, if everything was successful, you should see an output like this:
    user@linux:~/r8168-8.042.000$ lsmod | grep r8168
    r8168                 491520  0

    You can also check as well your ethernet device directly to see if the correct driver is loaded (special thanks goes to Tim which posted this in the comment section):

    user@linux:~$ sudo ethtool -i enp1s0
    driver: r8168
    version: 8.042.00-NAPI
    firmware-version:
    expansion-rom-version:
    bus-info: 0000:07:00.0
    supports-statistics: yes
    supports-test: no
    supports-eeprom-access: yes
    supports-register-dump: yes
    supports-priv-flags: no

    NOTE: You have to the change enp1s0 to the device name of your network card of course. This can be eth0, eth1, enp2s0, and so on.

    If your driver isn’t loaded until now, you should go with a reboot before further investigation.

That’s it

And that’s it. Now you’re ready to use your RTL8168/RTL8111 with the official Realtek drivers. If you have any questions and / or suggestions, please let me know in the comments.

OpenVPN Error: Linux route add command failed

OpenVPN Logo

Image source: openvpn.net

Everbody knows OpenVPN. A powerful and easy to configure VPN client, which is cross-platform available for BSD, Linux, MAC and Windows.
A lot of my Linux boxes are OpenVPN clients, starting with Virtual Machines as well as physical boxes. If I use my OpenVPN server as a default gateway, some machines having trouble to create the necessarily route. The output in the most cases is something like this:

Sun Jun 19 14:03:20 2016 /bin/ip route add 1.2.3.4/32 via 0.0.0.0
RTNETLINK answers: No such device
Sun Jun 19 14:03:20 2016 ERROR: Linux route add command failed: external program exited with error status: 2

So this means that the OpenVPN tried to create a new route with the help of the ip command which failed (error code 2). But how to fix this?

Add the route by your own

I’ve searched around the internet and nobody really had an answer to this. Well, the solution is rather simple. Directly after the successful connection to your OpenVPN server, add the route by your own. The following example would do this for the shown error above:

sudo route add -host 1.2.3.4 dev enp4s0

As you can see, there is no gateway address to reach the host. It’s simply the Ethernet device which is stated here (enp4s0 is the name of the first wired Ethernet device under openSUSE when using Network Manager (formerly known as eth0)).

This error also occurs, if you want to use a OpenVZ container as a OpenVPN client. By default, the first virtual network device of a OpenVZ container is called venet0. So you would have to enter the following command to get this error fixed:

sudo route add -host 1.2.3.4 dev venet0

After you added the host to your routing table with the correct outgoing network device, you’re ready to go to use the VPN as your default gateway.

Permanent Fix

To be honest, until now I wasn’t able to find a permanent fix for this. So this also means that you have to redo the route add command every time, when you have connected to your VPN.
If you know a permanent fix for this problem, just let me know in the comments below. Your help is appreciated 🙂