Server Move

Last week I moved our VLE (Moodle) from a P4 Dell server to a brand new AMD64 server. Aside from a few gotchas and stupid mistakes (which I shall elaborate on) it all went pretty well. Quick too. Let me explain how I did it.

Firstly, I had to get the new server setup. This was easy using my Linux distro of choice, Ubuntu. All I had to do was stick the AMD64 server ISO in and choose a 'LAMP' install. This sets up Apache2, PHP5 and MySQL5 for me. The machine had this installed in under 20mins.

Next, I had to do a backup of the old server (just in case!) . I dumped all the databases required. The VLE, room booking system and help desk system (these other systems are internal only, the joys of virtual web hosting). Then I rsynced the web sites (/var/www/sitename/*) and the apache2 configuration (/etc/apache2/*) to our backup machine.

Next I had to transfer the data across to the new server. The database dumps were easy. I just scp'd them across. I also scp'd across the apache2 config and the website. I just had to tarball them beforehand. Once across, I just decompressed them in the correct place.

The databases needed a little more work. I installed PHPMyAdmin (I'm lazy) and re-setup the databases and their users. I then imported the data from the command line using 'mysql' (There's too much data to upload via PHPMyAdmin, more on that later).

At this point I turned the old server off and set the new server to use it's IP addresses (we use IP based virtual hosting, so there are several IP aliases set on the one nic). Everything came back up ok and the VLE worked. Time to go home!

An Apt Quote

My last post on this subject generated quite a lot of controversy. So I thought I'd share a bit of history that turned up during my research into the subject. Here is a famous quote by A. C. Hobbs, an American lock picker who forced lock makers to improve their designs by publicly breaking locks at the Great Exhibition of 1851.

A commercial, and in some respects a social doubt has been started within the last year or two, whether it is right to discuss so openly the security or insecurity of locks. Many well-meaning persons suppose that the discussion respecting the means for baffling the supposed safety of locks offers a premium for dishonesty, by showing others how to be dishonest. This is a fallacy. Rogues are very keen in their profession, and know already much more than we can teach them respecting their several kinds of roguery.

Rogues knew a good deal about lock-picking long before locksmiths discussed it among themselves, as they have lately done. If a lock, let it have been made in whatever country, or by whatever maker, is not so inviolable as it has hitherto been deemed to be, surely it is to the interest of honest persons to know this fact, because the dishonest are tolerably certain to apply the knowledge practically; and the spread of the knowledge is necessary to give fair play to those who might suffer by ignorance.

It cannot be too earnestly urged that an acquaintance with real facts will, in the end, be better for all parties. Some time ago, when the reading public was alarmed at being told how London milk is adulterated, timid persons deprecated the exposure, on the plea that it would give instructions in the art of adulterating milk; a vain fear, milkmen knew all about it before, whether they practiced it or not; and the exposure only taught purchasers the necessity of a little scrutiny and caution, leaving them to obey this necessity or not, as they pleased.

-- From A. C. Hobbs (Charles Tomlinson, ed.), Locks and Safes: The Construction of Locks. Published by Virtue & Co., London, 1853 (revised 1868).

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Security through Obscurity

This is a follow up to my 'The trouble with NAT' post. I thought I should explain the other aspect to the thread that surfaced as it progressed as it touch on some other very interesting (and apparently controversial) points of view. As I previously explained the original poster of the thread had hit a brick wall in attempting to access a website. If you want to know the full details of why and how you really should read my previous blog entry. If not then read on.

After a while a possible solution emerged to the IP ban. Use an anonymous proxy. There is however a catch with that. Most educational institutions use web filtering software to block certain categories of websites. There's the usual obvious stuff like porn, warez, gambling etc. But most also attempt to block sites that have Trojans/viruses and most relevant for our situation sites that allow users to bypass the filtering. The vast majority of these only filter based on the sites domain or the URL.

This is hopelessly inflexible. Your fighting a losing battle trying to keep up with all the new sites going up on a daily basis. No, a much more sensible and proven method is to filter based on the content of the actual web pages. This how your virus scanner and spam filter works after all! To that end I use a web filter called DansGuardian. It does domain, URL and content filtering plus it can scan for viruses.

However it seems quite a few schools are using inferior systems (and paying for them to boot!). This got me into a little trouble and a few flames. When I pointed out that the original poster could setup a simple PHPProxy based system that would solve his problem my post was moderated. Now as far I'm concerned there really isn't any point.

Not withstanding the fact PHPProxy had been mentioned previously to illustrate exactly the problems I've outlined. I feel that the tools themselves are not to blame. There always will be someone out there who wishes to take freely available information and do something harmful or illicit on their work/school/college network. You just have to prepare your systems as secure as possible and have monitoring systems in place to catch them. Assuming you do then hope your AUP is sufficient to deal with them when you catch them.

The trouble with NAT

There was a forum topic earlier this week on Edugeek (a very good site, recommended) concerning a user who was at college and he had lost access to some online forums. This was because his college uses NAT to allow the many PC's on their private LAN to access the Internet simultaneously. The forum admins had banned the IP of the problem user but because all the users at the college appear as coming from one IP the forum admins had effectively banned the entire college from their site. Naturally he had contacted the admins to re-establish access. They apparently declined.

I personally have seen the same problem on Wikipedia. IP bans are quite common for 'anonymous' editors who vandalise and blank pages. In fact I raised this issue not long ago with our LEA because the proxy servers the schools used were blocked from editing. There is little that they can do of course. Happily with Wikipedia it's possible to get round the editing ban by creating a user account. Any edits will then be attributed to the account and not the IP even the IP is blocked from editing.

I suspect NAT will be with us for a long time to come and this is one of many unfortunate side effects. Of course it has it's advantages for sharing the Internet and providing security for machines behind the NAT gateway. But it really isn't the way the Internet is supposed to work. A lot of software (Video conferencing, Instant Messaging, VoIP, P2P apps like Bit torrent for example) assumes end to end compatibility which has to be hacked around to work with NAT.

Roll on IPv6!

The name game

If you're wondering how and why I came up with the name well it's pretty simple really. It's basically play on words from one of my favorite Indy PC games. But first some background. I play a lot of space/strategy games. The sub-genre close to my heart is one called 4X. These are very complex games that take weeks (or months!) to complete with plenty of re playability. However the amount of time and effort puts a lot of people off. Fortunately, there's a game called Strange Adventures in Infinite Space which allows for a lot of strategy but packs it in to a mere 5 minutes of game play. Just perfect for those slow lunchtimes. There's a free demo available for download and the system requirements are fairly modest.