Free multi-domain SSL certificates from WoSign and HAProxy OCSP stapling

Since everyone now can get free 2-year multi-domain certificates from WoSign, I grabbed one for one of my web sites. However, WoSign’s OCSP server is located in China which may, depending on your and your server’s location, increase latency once the web browser is verifying the certificate’s revocation status. In my case from Europe:

PING ( 56(84) bytes of data.
64 bytes from icmp_seq=1 ttl=53 time=428 ms
64 bytes from icmp_seq=2 ttl=53 time=347 ms
64 bytes from icmp_seq=3 ttl=53 time=312 ms
64 bytes from icmp_seq=4 ttl=53 time=328 ms
64 bytes from icmp_seq=5 ttl=53 time=313 ms

OCSP stapling comes in handy to reduce the latency for the revocation status check, again, depending on your clients and your server’s location.

Here’s the all-in-one shell script in /etc/cron.daily I’m using…

  1. to create the domain’s OCSP file for HAProxy
  2. to inject the latest OCSP data into a running HAProxy instance using its stats socket
OCSP_URL=`/usr/bin/openssl x509 -in $SERVER_CERT_FILE -text | grep -i ocsp | cut -d":" -f2-2,3`

/usr/bin/openssl ocsp -noverify -issuer $ROOT_CERT_FILE -cert $SERVER_CERT_FILE -url "$OCSP_URL" -respout $OCSP_FILE -header Host `echo "$OCSP_URL" | cut -d"/" -f3`
echo "set ssl ocsp-response $(/usr/bin/base64 -w 10000 $OCSP_FILE)" | socat stdio $HAPROXY_SOCKET

To check if OCSP stapling works:

openssl s_client -connect -tls1 -tlsextdebug -status

or for SNI-only configurations:

openssl s_client -connect -servername -tls1 -tlsextdebug -status

If it works, there should be an OCSP section in the response like this:

OCSP response:
OCSP Response Data:
    OCSP Response Status: successful (0x0)
    Response Type: Basic OCSP Response
    Version: 1 (0x0)
    Responder Id: C = CN, O = WoSign CA Limited, CN = WoSign Free SSL OCSP Responder(G2)
    Produced At: Mar  8 14:01:14 2015 GMT

A few notes:

  1. HAProxy’s stats socket needs to be enabled
  2. wosign-root-bundle.crt was taken from the Apache bundle in the certificate .zip file I received from WoSign
  3. /etc/haproxy/certs.d/domain.crt contains the private key and the certificate bundle from the “for Other Server” directory, however you could remove the last certificate since it’s the root CA cert.
  4. Requires HAProxy >= 1.5
  5. If socat is missing: apt-get install socat in Debian/Ubuntu
  6. Always aim for an A or A+ grade: SSL Server Test

How to set up a transparent VPN Internet gateway tunnel using OpenVPN

I created a transparent VPN Internet gateway tunnel (sorry, couldn’t come up with a better name for it) using OpenVPN and my new Odroid-C1 Linux mini computer. However, this will work with any Linux PC (including the Raspberry Pi). The beauty of a transparent VPN gateway is that a device in the LAN doesn’t have to know anything about the VPN. I don’t have to remember to turn on the VPN nor does it drain the battery on mobile devices to encrypt and decrypt the packets. The VPN is just “there”. On the other hand, mostly for performance reasons, I don’t want to encrypt all traffic leaving my home LAN, that’s why I didn’t set up the VPN in the existing router. vpn-gatewayI wanted to be able to choose, on a per-device basis, which devices will route their traffic unencrypted to my ISP and which devices will get their traffic encrypted and forwarded to the remote VPN server using a second gateway in my LAN. And all this without additional subnets in my LAN, VLANs or additional WiFi or Ethernet-adapters. This may not look like the brightest idea to everyone but it works for me and I wanted to document it to save time if I have to set it up again. This is not a step-by-step tutorial but should provide enough pointers to get started.

Continue reading “How to set up a transparent VPN Internet gateway tunnel using OpenVPN”

How to install Kodi on an ODROID-C1 as a standalone mediacenter

The ODROID-C1 ist just too cool not to have. This feature-packed ARM7 quad core Linux mini computer comes with an incredible price tag of $35. However, with all the accessories (RTC-battery, power supply, case, mini-HDMI cable, eMMC card, remote control…) and shipping from Korea, the final price is around $100. It’s going to replace my Raspberry Pi which I initially intended to use as a media center but it always felt a little too slow for the task, even with the highly tuned Raspbmc.

Since I wanted the ODROID-C1 to run Kodi without a desktop manager (but with an Ubuntu repository), I started off with the Ubuntu 14.04 minimal image provided by Hardkernel. Don’t forget to resize the root partition to its true size once the ODROID-C1 is up and running (and reboot again!). I’m recommending the Odroid-Utility for doing this. And while you’re at it, make sure to “Update udev rules for ODROID subdevices” in the “Update your Kernel/Firmware” menu. If you forget this step, Kodi might abort with ERROR: failed to initialize egl display.


I’m assuming here that the ODROID-C1 has network connectivity and you’re logged in as root.

With a few adaptations, this information was taken from my existing post on how to install Kodi on an Ubuntu 14.04 server. Continue reading “How to install Kodi on an ODROID-C1 as a standalone mediacenter”

How to set up a virtual KVM/VNC console on your OVH server

Want to install your own image on a OVH Kimsufi or SoYouStart server? Want to install an official image on your server instead of the pre-built OVH OS templates? Want to encrypt the home directory at install-time? Want to use RAID 5 using mdadm on one of those SSD equipped SoYouStart servers? Or do you want to use a more refined, custom partition layout which is not supported by the OVH partitioner? And you want this without having access to or having to pay for a KVM console?
Continue reading “How to set up a virtual KVM/VNC console on your OVH server”

KVM VM waits forever / stuck at kernel selection screen

If a KVM virtual machine has not been properly shutdown, it may wait forever at the boot up kernel selection screen for user input. You won’t see any output when trying to virsh console into the VM from the host. You have to fire up a remote VNC session in order to press enter.

In Ubuntu Server you can override this behaviour by adding the following line to /etc/default/grub:


Don’t forget to run update-grub afterwards.