HowTo: Setup an account to have SFTP access but not SSH access

Tutorials
For those of us who like to outsource work, there comes a time where your developer needs access to your server to upload files, but you don't want them to have shell access to execute commands. You are probably also wanting to prevent them from seeing your other data on the server too, so we need to prevent them from being able to go outside of their Home folder. This process is called "chroot jailing" them to a specific folder. Here is how you setup an Ubuntu 16.04 server to do just that. (more…)
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HowTo: Install Flumotion Streaming Server on Ubuntu 14.04

Tutorials
Flumotion Streaming Server is a great open-source application that is available in the Ubuntu repositories that can easily allow you to broadcast a live stream from a video camera, or broadcast pre-recorded media. The end-user can view this media in any capable HTML5 web browser such as Google Chrome. Unfortunately Flumotion (version 0.10.0-1 at the time of writing) relies on some deprecated Twisted Python network functions that prevent the software from working properly on any release of Ubuntu from 13.04 and upwards. The obvious solution is to simply install Flumotion under Ubuntu 12.04 but then you will find that Flumotion in the 12.04 repository is buggy and out of date anyway, requiring you to update Flumotion from the official developer PPA to the stable release that is already in Ubuntu 14.04. There is…
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HowTo: Setup Darik’s Boot and Nuke (DBAN) to automatically erase storage devices via PXE boot

Tutorials
Darik's Boot and Nuke (abbreviated as DBAN) is a popular tool used by many organisations and individuals to securely erase hard-drives prior to disposal, or perhaps just to fix Windows problems ;) . It typically comprises a small 15MB ISO image that you can burn to CD or make a bootable USB stick from so you can boot up a PC on it and set about erasing all detected storage devices. When you're doing a lot of machines, however, booting a CD is tedious, especially when you accidentally scratch the disc and need to burn a new one. Using a USB stick and either misplacing it, or forgetting to remove it before erasing starts means you lose the content of the boot stick too. Wouldn't it be nice to be able…
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HowTo: Fix Postgrey not working after upgrading from an older version of Ubuntu to a newer version.

Tutorials
Scenario: You've got some Postfix mail servers running with Postgrey for anti-spam greylisting. They're all using older versions of Ubuntu such as 10.04 LTS. You've decided that it's time to upgrade them to the next LTS, Ubuntu 12.04. You do the upgrade and it goes without a hitch. You restart the server, everything looks good, until you start seeing this message in your server's mail log:   Jan 23 21:17:58 mymailserver postfix/smtpd[7976]: connect from somecompany.com[100.200.300.400] Jan 23 21:17:59 mymailserver postfix/smtpd[7976]: warning: connect to 127.0.0.1:10023: Connection refused Jan 23 21:17:59 mymailserver postfix/smtpd[7976]: warning: problem talking to server 127.0.0.1:10023: Connection refused Jan 23 21:18:00 mymailserver postfix/smtpd[7976]: warning: connect to 127.0.0.1:10023: Connection refused Jan 23 21:18:00 mymailserver postfix/smtpd[7976]: warning: problem talking to server 127.0.0.1:10023: Connection refused Jan 23 21:18:00 mymailserver postfix/smtpd[7976]: NOQUEUE: reject:…
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HowTo: Fix networking not working after installing Ubuntu Desktop from a PXE-booted Live Environment

Tutorials
Scenario: You've setup a PXE server. You've setup an Ubuntu Live CD to boot over your network via PXE. Everything works well. You then decide to install a fresh Ubuntu Desktop installation from your PXE-booted environment. All goes well. The install finishes and your system reboots. When the system comes up, you discover that there's no network connections. Ethernet doesn't work, but wifi probably is working OK, or you can't get wifi working yet because you need to install a closed-source driver for it. You check the Network Manager and find that there is no automatically defined ethernet connection such as "Auto eth0". What's the go? Here's how to fix it. (more…)
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HowTo: Create a Diskless workstation that boots from PXE using Ubuntu

Tutorials
Diskless booting is where a PC starts up purely from a network connection. It does not have a physical hard-drive in it to start from in the traditional manner. Why would you want to do this? Well, say for example you have a MythTV Frontend PC. For the most part, most Frontends are dedicated PC's connected to a TV or projector that are not used for any other purpose, so technically there is really no need to have a hard-drive inside one as nothing new will ever be stored (all the media is streamed from the Backend server). There's also the added bonus of less noise by not having a hard-drive installed. Another good example of using a Diskless boot environment is for performing offline virus scans of Windows based…
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HowTo: Automatically determine your public IP address and email it periodically

Tutorials
Let's say you are running a poor man's website where you are just testing stuff but have no real intention of buying a domain name or paying your ISP to give you a static IP address. If you want to access your test site remotely, you need to know your public IP address, however your home ISP gives you a dynamic public IP address and every time you have a power failure, or reboot your router, you are assigned a brand new public IP address. This makes it very annoying if you are testing your site remotely. Sure, you could use a Dynamic DNS service to keep track of when your public IP address changes, but what if you have a paranoid client who does not want to use even…
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HowTo: Get an Ubuntu Live CD to boot off a PXE server

Tutorials
Following my article about creating your own PXE network boot server, here is the first practical use you can put it to - taking the Ubuntu Live CD and turning it into a network-bootable version! Network booting the Live CD has obvious advantages - aside from booting faster than CD (especially on a gigabit network), it is indispensable as an emergency boot medium in a workplace environment, especially for broken Windows systems, and allows for Ubuntu effortless installations on netbook PC's that don't have optical drives and saves you having to have a USB stick handy. (more…)
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HowTo: Setup your own PXE Boot Server using Ubuntu Server

Tutorials
The Preboot eXecution Environment (PXE) provides a means of starting up a PC using a network adapter instead of the traditional method of hard-drive, USB flash stick, CD or floppy disk. Why would you want to boot a PC from the network? Well, it opens the door to booting diskless workstations, eg: Internet Cafe PC's, or if you regularly install tens or hundreds of PC's, you can start the installer on all those machines at once without needing to have individual boot/install media for each machine. You can even use Linux PXE for starting Microsoft Windows network installers and tools. This article is going to show you how to setup a standard Ubuntu 10.04 Lucid Lynx Server (will also work with Ubuntu 12.04 and 14.04) to respond to a PXE…
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