haproxy is one of the best known and widely used Open Source load balancers out there and a strong competitor to nginx.
haproxy is used by many large sites per Wikipedia:
HAProxy is used by a number of high-profile websites including GoDaddy, GitHub,........
Why choose OpenVPN instead of a firewall appliance?
OpenVPN can be a reliable and easy replacement for traditional hardware or just be an additional tool that your company uses so that the firewall can focus on its job rather than acting as a VPNappliance at the same time.
When comparing OpenVPN with traditional firewal........
If you've just installed VBox and it is not starting or working, the most common problem is usually that you don't have your kernel source installed, which means there is no kernel driver for vbox so it can't work.
You may get an error that says "Kernel driver not installed" in your Virtualbox.
So the first thing you should do is install your kernel source by running this:
sudo apt-get install linux-headers-`uname -r`........
If you move your hard drive(s) around to other computers/servers, you'll find that your eth0 keeps getting higher, the first time it will become eth1 and then eth2 etc and even higher if your server has dual or quad NICs. The reason is that udevd basically assigns eth0 tot he first NIC it finds and remembers it, if it encounters a NIC with a differentMAC, it assigns it one higher (eg. eth1).
See the example below, I have eth2 now so how doI fix it?........