Iptables-apply or how to avoid unnecessary site visits when changing firewall configuration

Today’s post is definitely of the short and sweet variety. I happened across the file list for iptables the other day and noticed a binary I had not come across before “iptables-apply”. Iptables-apply is a script that applies firewall rules and then waits a configurable amount of time, for user input, to confirm the changes […]

Transparent bridging firewalls

The commands in this article can be used on any Ubuntu/Debian machine. A transparent bridging firewall is a firewall which can be inserted anywhere on a network, but usually between the network segment containing internet access and the rest of a LAN. Generally they are used to silently police and log traffic from the network […]

Ubuntu as a wireless 80211g/n access point/router

Following relatively recent improvements in the Linux wireless stack and driver support it is now possible to setup a Linux machine as an access point, even if you don’t have an Atheros chipset (which was historically the case). Support is patchy but I would say there is a good chance you can do this if […]

Remove residual config files in Ubuntu – A one liner

I have spent literally hours over the last year or two searching for an elegant way to remove configuration files left over from package installs, in a command line environment, with Ubuntu. Googling would provide a frustrating list of solutions that would either involve installing extra packages, using a complicated command line, or script, solutions […]

Remotely upgrading a server from 32 to 64 bit linux

This post isn’t designed to be a “how to” merely an overview of how I achieved the subject. It is possible to do this without any physical intervention but in practice I have had to visit site at least once to fix a boot error on every one I have done. Disclaimer:- When attempting this […]

Setup DNS, DHCP and Content Filtering using DNSMASQ and HAVP in Ubuntu.

The idea here is to setup DNSMASQ and HAVP to provide DNS, DHCP and content filtering in a Windows 7/Vista/XP client environment on Ubuntu Server Edition. DNSMASQ is a light package which will provide DNS caching and DHCP to a network (amongst other things). HAVP is a proxy server which uses a third party virus […]

A cost effective alternative to KVM over IP switches

Whether in a co-location centre or at a remote site, looking after a server when you aren’t there in person can be a challenge, particularly if you are conscientious and update your servers regularly – updating a Windows server almost always requires reboot, updating a Linux server will require reboot if the kernel has been […]

Recover a failing Windows hard disk using only free software and your Windows CD.

Scenario. You have a Windows machine which will not boot up but you can still access the disk, even though it makes various clunking and thunking noises. Solution. Install a new hard disk and Partedmagicos on a USB stick or CD and run either “ntfsclone” (the easiest and quickest option) or “dd_rescue”. If the NTFS […]

Wake On LAN over wireless

What is it? Wake On LAN is a mature technology for switching on computers over a network or remotely. Why would I want it? Perhaps you are a techy such as myself and you want to be able to switch customers computers on and work on them remotely (saves having to tell people to leave […]

The importance of a minimal firewall.

I have long been an avid user of the well known interface to iptables – Shorewall. Of late though I have suspected it is slowing my network down. I once decided to see what actual iptables rules it was creating and ran “iptables -L”. There was a lot of output and I wasn’t sure was […]