Debian Wheezy Xen + Guest Howto

October 8th, 2014

Xen is usually my go to virtualization technology for Linux. Here’s a HOWTO on setting up Xen on Debian Wheezy and the first guest virtual machine.

First step is getting the required packages:

apt-get install xen-linux-system xen-tools xen-utils-4.1 xen-utils-common xenstore-utils xenwatch

Now, we’ll need to specify the Xen kernel as the default boot kernel on the host, and then reboot:
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Full NAT, DNAT and SNAT aka 1:1 NAT, 1 to 1 NAT

February 10th, 2010

Full NAT, DNAT and SNAT aka 1:1 NAT, 1 to 1 NAT – this is used when you want to map a dedicated external IP on an external interface to another IP on a separate interface with everything routed between them.


echo 1 > /proc/sys/net/ipv4/ip_forward

iptables -t nat -A PREROUTING -i ${EXTERNAL_IF} -d ${EXTERNAL_IP} -j DNAT –to-destination ${INTERNAL_IP}
iptables -t nat -A POSTROUTING -o ${EXTERNAL_IF} -s ${INTERNAL_IP} -j SNAT –to-source ${EXTERNAL_IP}
route add -host ${EXTERNAL_IP} ${INTERNAL_IF}

Linux IP Address Configuration Static or DHCP

January 18th, 2009

It’s simple really..

You can define a static IP as follows:

ifconfig <interface> <ipaddress> netmask <mask> broadcast <broadcast>
e.g. ifconfig eth0 netmask broadcast

You can then define a route out to the internet:

route add default gw <router>
Which has the same effect as: route add -net <router>
i.e. route add default gw

Or if you’d like to acquire an address via a local DHCP server:

dhclient <interface>
e.g. dhclient eth0

That’s all there is to it! Now.. these settings won’t stick on reboot, you’ll have to refer to your distro’s startup files. On debian you want /etc/network/interfaces

A sample stanza for the above configuration:

auto eth0
iface eth0 inet static

All done!

Quick Linux and Windows OpenVPN HOWTO and tutorial, including VPN routing

September 15th, 2008

OpenVPN is a popular Windows/Linux VPN Server/Client pair. I think there’s a separate GUI available for it if you’re so minded. This howto will cover command line usage only.

I’ll provide example configuration based on a Linux server and a Windows client, however the same applies pretty easily if you wanted to mix and match.

On Debian, apt-get install openvpn. On any other linux distro, use your own package manager or alternatively download from source and compile.
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