Calculating performance of outdoor wireless network links

Posted on January 15, 2017 by MadPsy

This article contains information on how to calculate the operating margin of a wireless 802.11 network using a known distance between the two points.

fresnel

I wrote this quite a while ago and although the throughput of wireless links has dramatically increased the basic theory still applies. Of course we now have 5GHz available, which is very useful for this application. You should be able to substitute ‘f’ for 5000MHz and the maths will still work.

You can now get a 150mbps PTP link over 15km using equipment that costs £160 for both ends – that’s the entire cost of the system (minus a couple of poles and brackets). Crazy value for money when you think about it. The Ubiquiti NSM5 NanoStation is one such example. The Ubiquiti product range is pretty impressive to say the least. The NSM5 seen below is the big brother of the LOCOM5, which at £125 can still do 10km at the same rate and are around half the size.

nsm5-kit

If you are considering an outdoor wireless link, give this article a read so you understand how high above objects you need to mount your shiny new kit!

That’s not a server, THIS is a server!

Posted on April 4, 2016 by MadPsy

I thought a wee article on what a server is and why they are expensive compared to your average PC might be interesting. When you hear someone say they have built a server for the house what they usually mean to say is they’ve built a PC and have it running various applications which serves ‘stuff’. A real server is a different beast all together.

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So what makes a server a server? It boils down to the hardware feature set. Sure, you can get low-end servers which are nothing more than a PC in a fancy rack mount chassis, but lets take a look at higher end goodness.

How To Configure Tor On Your Network

Posted on November 15, 2015 by MadPsy

Tor (‘The Onion Router’) is by far the most popular solution for anonymous browsing, with over 6000 relays and 2.5 million active users. I’m going to look at how to configure Tor on your network, in a variety of ways. The so called ‘Dark Web’ seems to get a bad press, maybe because of illegal sites like Silkroad, but it’s actually an invaluable resource for citizens or visitors to countries who have severe Internet censorship (including the UK!). Even Facebook has a .onion address, as does the DuckDuckGo search engine and Aphex Twin’s ‘Syro’ album.

By far the simplest and most secure way of using Tor is to install the Tor Browser. It’s dead simple and takes literally a few minutes. However, depending on your goal, there are other ways to use Tor. I’m going to look at a few ways to deploy Tor, including the pros and cons of each. These are:

Using the Tor Browser Bundle
Configuring a Tor SOCKS proxy
Creating a transparent Tor network

Providing Free WiFi For Anyone To Use

Posted on November 8, 2015 by MadPsy

As the UK government have announced they wish to classify Internet access as a public utility (implying it shouldn’t be a privilege but should be more like electricity etc) I thought I’d share how I have opened my Internet connection for anyone to use. As long as you can receive the signal you can connect and browse to your heart’s content without any keys or passwords.

free-internet

Firstly, this is against the T&C’s of most ISPs, including mine. There’s a few (il)logical reasons for that but it’s mainly revenue protection. Even though they know a single connection would be perfectly suitable for many households to share, they would obviously lose money if everyone did that. Namely because, unlike other utilities, Internet access is generally not metered, meaning it’s a fixed cost per household per month. If your neighbour cannot afford their own Internet access or for whatever reason cannot get a contract then I feel it’s only fair to allow them to use mine. With talk of some people not being able to afford heating during the winter it’s hardly appropriate to expect them to also afford broadband. Who needs Internet access though? I mean it’s not like online shopping is generally cheaper or anything, not to mention almost everything is moving towards e-billing, right?

I’m not going to suggest everyone should just blindly open up their WiFi router for anyone to use but here’s how I’ve achieved this safely.

Edgerouter: Ad Blocking at a Network Level

Posted on November 1, 2015 by MadPsy

We are going to look at how to implement advert blocking on an Edgerouter at a network level using DNS. This can also be applied to other software routing devices. There are many ways to block adverts these days – various browser plugins, browsers with built in blocking, proxy servers (normal or transparent) and also with DNS. Whatever your thoughts are regarding websites using adverts for revenue generation, the fact is many sites have obscene amounts of ads.

adblock

Quite often adverts are designed to dupe you by purposely making them look like the link you are actually after. A typical example of this is where you have a ‘download’ button which is actually an advert to download something else entirely. This is not only deceitful but is down right unacceptable. Until all adverts become unobtrusive, targeted and honest I will keep blocking them; even if this means I can’t access websites which block you for blocking ads.

Use IPv6 even if your ISP doesn’t support it

Posted on October 20, 2015 by MadPsy

Sometimes you just have to know something exists before you look into it. IPv6 tunnels may well be a good example. Many ISPs are stuck in the dark ages, what with their archaic attitudes and red tape procedures longer than a trip to Mars.

It’s dead simple to get IPv6 working at home via an IPv6 tunnel broker.

helogo

I guess this is somewhat ironic, given their 90’s style logo and website, but these guys provide the tools you need to get your Internet connection this side of the new millennium. Guess what – it’s FREE!

How To: Read Your Neighbours Facebook Private Messages

Posted on October 17, 2015 by MadPsy

For a casual bit of weekend fun I thought I’d share a potential method for obtaining your neighbour’s Facebook password. This is purely educational and I used my own systems to do this but it highlights how potentially easy it can be to obtain someone’s login credentials to any website.

We are going to utilise various attack vectors to demonstrate the methodology of the process. The story starts with a hypothetical situation.

Horrible IPv6 to IPv4 Hack

Posted on October 15, 2015 by MadPsy

With the ever greater need for the adoption of IPv6 in the Internet world it’s high time people started dual stacking services on both IP versions. Sadly, sometimes this is not possible when particular software hasn’t caught up with 1995.

This is especially frustrating when, for one reason or another, you want to use a single hostname for both services which support v6 and those which don’t.

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The reason this is complicated is because a single hostname Read More »

Half-Arsed DNS Providers should be shot

Posted on October 13, 2015 by MadPsy

We all know when you buy a domain name the registrar often provides a complimentary DNS service for you to use. Gee thanks you might think. Turns out they’re almost all half-arsed and generally a bit shit.

DNS

Lets take 123-reg.co.uk and easily.co.uk as examples. Read More »

TP-Link SG108E – Nasty £25 Gigabit Switch

Posted on October 13, 2015 by MadPsy

TP-Link are pretty much synonymous for producing feature rich, solid and cheap networking products. Their SG108E Gigabit Switch should be decent.. surely.

Ermm… well lets just say it’s cheap and cheerful. Whilst they have gone to the effort of writing the managed firmware code in the device itself, the management interface is shocking.

There it is – a cute 8 port ‘managed’ switch. I expect some things at minimum from a managed switch. Read More »

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