Network Hacks

118 Articles

That’s It, No More European IPV4 Addresses

November 29, 2019 by 78 Comments

When did you first hear concern expressed about the prospect of explosive growth of the internet resulting in exhaustion of the stock of available IP addresses? About twenty years ago perhaps? All computers directly connected to the internet must have an individual unique address, and the IPv4 scheme used since the 1980s has a 32-bit address space that provides only 4,294,967,296 possibilities. All that growth now means that IPv4 addresses are now in short supply, and this week RIPE, the body which allocates them in Europe, has announced that it no longer has any to allocate. Instead of handing new address blocks they will instead now provide ones that have been relinquished for example by companies that have gone out of business, and parties interested can join a waiting list.

Is the Internet dead then? Hardly, because of course IPv6, the replacement for IPv4, has been with us for decades and has a much larger 128-bit address space. The problem is that there is a huge installed base of IPv4 infrastructure which has always been cited as the reason to delay its adoption, so the vast majority of the internet-connected world has remained with IPv4. Even in an IPv4 world there are opportunities to be more efficient in the use of addresses such as the network address translation or NAT that many private networks use to share one address between many hosts, so it’s not quite curtains for your smart TV or IoT light bulb even though the situation will not get any easier.

The mystery comes in why after so many years we still use IPv4 so much. Your home router and millions like it will pick up an IPv4 address from your broadband provider’s pool, and there seems little reason why it can not instead pick up an IPv6 address and contain a gateway between the two. The same goes for addresses outside the domestic arena, and even in out community we find that IPv6 networks at events are labelled as experimental. Perhaps this news will spur the change, but meanwhile we don’t expect to be using an IPv6 address day-to-day very soon.

We know among Hackaday’s readership there will be people close to the coalface when it comes to IPv6 adoption. As always the comments are open, and we’d like to hear your views.

Header: Robert.Harker [CC BY-SA 3.0].

Ethernet, Over DC Power

November 14, 2019 by 48 Comments

We’re used to extending our network connections and being no longer constrained in our use of Ethernet by proximity to a switch or hub. Our houses routinely contain wireless networks, and of course powerline-Ethernet units passing data over our mains wiring. [Peter Franck] had a similar problem but without the mains power, for a distributed sprinkler system he needed to send Ethernet over DC cables.

The solution is a surprisingly simple one, taking one of those powerline Ethernet units and converting it by removing its mains power section. These devices contain the Ethernet and powerline modem chip with its associated circuitry, and a small switch-mode power supply. He’s removed the power supply and put in a capacitive coupling to the DC cabling, resulting in a relatively inexpensive DC powerline network device.

Powerline Ethernet devices are not without their own issues, for instance they are not popular with radio amateurs due to their effect on the RF noise floor. We’d therefore be curious to see what the RF emissions are like for this hack, but we still think it’s a useful weapon in the armoury as well as something to do with all those surplus powerline Ethernet bricks.

Network Booting The Pi 4

November 11, 2019 by 33 Comments

We’ve talked about PXE booting the Raspberry Pi 3B+, and then looked at the Raspberry Pi 4 as a desktop replacement. But there’s more! The Pi 4 sports a very useful new feature, the flashable bootloader. Just recently a beta version of that bootloader was released that supports PXE  — booting up over the network — which has become a must-have for those of us who have had consistently bad experiences with root filesystems on SD cards.

Pi with no SD CardWhat are the downsides, I hear you ask? You might see slower speeds going across the network compared to a high quality SD card, particularly with the Pi 4 and its improved SD card slot. PXE does require an Ethernet cable; WiFi is not enough, so you have that restriction to contend with. And finally, this isn’t a portable option — you are tethered to that network cable while running, and tethered to your network to boot at all.

On the other hand, if you’re doing a permanent or semi-permanent install of a Pi, PXE is absolutely a winner. There are few things worse than dragging a ladder out to access a Pi that’s cooked its SD card, not to mention the possibility that you firewalled yourself out of it. Need to start over with a fresh Raspbian image? Easy, just rebuild it on the PXE server and reboot the Pi remotely.

Convinced PXE is for you? Let’s get started! Continue reading “Network Booting The Pi 4” →

5G Is For Robots

October 30, 2019 by 43 Comments

Ecclesiastes 1:9 reads “What has been will be again, what has done will be done again; there is nothing new under the sun.” Or in other words, 5G is mostly marketing nonsense; like 4G, 3G, and 2G was before it. Let’s not forget LTE, 4G LTE, Advance 4G, and Edge.

Just a normal everyday antenna array in a Seattle parking garage.

Technically, 5G means that providers could, if they wanted to, install some EHF antennas; the same kind we’ve been using forever to do point to point microwave internet in cities. These frequencies are too lazy to pass through a wall, so we’d have to install these antennas in a grid at ground level. The promised result is that we’ll all get slightly lower latency tiered internet connections that won’t live up to the hype at all. From a customer perspective, about the only thing it will do is let us hit the 8Gb ceiling twice as faster on our “unlimited” plans before they throttle us. It might be nice on a laptop, but it would be a historically ridiculous assumption that Verizon is going to let us tether devices to their shiny new network without charging us a million Yen for the privilege.

So, what’s the deal? From a practical standpoint we’ve already maxed out what a phone needs. For example, here’s a dirty secret of the phone world: you can’t tell the difference between 1080p and 720p video on a tiny screen. I know of more than one company where the 1080p on their app really means 640 or 720 displayed on the device and 1080p is recorded on the cloud somewhere for download. Not a single user has noticed or complained. Oh, maybe if you’re looking hard you can feel that one picture is sharper than the other, but past that what are you doing? Likewise, what’s the point of 60fps 8k video on a phone? Or even a laptop for that matter?

Are we really going to max out a mobile webpage? Since our device’s ability to present information exceeds our ability to process it, is there a theoretical maximum to the size of an app? Even if we had Gbit internet to every phone in the world, from a user standpoint it would be a marginal improvement at best. Unless you’re a professional mobile game player (is that a thing yet?) latency is meaningless to you. The buffer buffs the experience until it shines.

So why should we care about billion dollar corporations racing to have the best network for sending low resolution advertising gifs to our disctracto cubes? Because 5G is for robots.

Continue reading “5G Is For Robots” →

Using PoE With A Raspberry Pi 3 For About Two Bucks

September 30, 2019 by 29 Comments

When the Raspberry Pi 3 Model B+ was announced in March of 2018, one of its new features was the ability to be (more easily) powered via Power-over-Ethernet (PoE), with an official PoE HAT for the low price of just twenty-one USA bucks. The thing also almost worked as intended the first time around. But to some people this just isn’t good enough, resulting in [Albert David] putting out a solution he calls “poor man’s PoE” together for about two bucks.

His solution makes it extra cheap by using so-called passive PoE, which injects a voltage onto the conductors of the network cable being used for PoE, without bothering with any kind of handshake. In general this is considered to be a very reliable (albeit non-standard) form of PoE that works great until something goes up in smoke. It’s also ridiculously cheap, with a PoE injector adapter (RJ-45 plug & 2.1×5.5 mm power jack to RJ-45 jack) going for about 80 cents, and a DC-DC buck converter that can handle the input of 12V for about 50 cents.

The rest of the $2 budget is mostly spent on wiring and heatshrink, resulting in a very compact PoE solution that plugs straight into the PoE header on the Raspberry Pi 3 board, with the buck converter outputs going into the ground and +5V pins on the Raspberry Pi’s GPIO header.

A fancier solution would implement any of the standard PoE protocols to do the work of negotiating a suitable voltage. Maybe this could be the high-tech, $5 solution featuring an MCU and a small PCB?

A New Way To Remote Terminal

August 9, 2019 by 13 Comments

Thanks to the wonders of the internet, collaborating with others across great distances has become pretty simple. It’s easy now to share computer desktops over a network connection, and even take control of another person’s computer if the need arises. But these graphical tools are often overkill, especially if all we really need is to share a terminal session with someone else over a network.

A new project from [Elis] allows just that: to share an active terminal session over a web browser for anyone else to view. The browser accesses a “secret” URL which grants access to the terminal via a tunnel which is able to live stream the entire session. The server end takes care of all of the work of generating this URL, and it is encrypted with TLS and HTTPS. It also allows for remote control as well as viewing, so it is exceptionally well-featured for being simple and easy to run.

To run this software only a binary is needed, but [Elis] has also made the source code available. Currently he finds it a much more convenient way of administering his Raspberry Pi, but we can see a lot of use for this beyond the occasional headless server. Certainly this makes remote administration easy, but could be used collaboratively among a large group of people as well.

Doing 10 Gigabit Networking At Home, The Cheap Way

July 24, 2019 by 53 Comments

For the vast majority of us, Gigabit Ethernet is more than enough for daily tasks. The occasional big network file transfer might drag a little, but it’s rare to fall short of bandwidth when you’re hooked up over Cat 6. [Brian] has a thirst for saturating network links, however, and decided only 10 Gigabit Ethernet would do.

Already being the owner of a Gigabit Ethernet network at home, [Brian] found that he was now regularly able to saturate the links with his existing hardware. With a desire to run intensive virtual machines on his existing NAS without causing bandwidth issues, it was time for an upgrade. Unfortunately, the cost of rewiring the existing home network to Cat 6 and procuring hardware that could run 10 Gigabit Ethernet over copper twisted pair was prohibitively expensive.

It’s a little ungainly, but it does the job.

Instead, [Brian] decided to reduce the scope to connecting just 3 machines. Switches were prohibitively expensive, so each computer was fitted with twin 10 Gigabit interfaces, such that it could talk to the two other computers. Rather than rely on twisted pair, the interfaces chosen use the SFP+ standard, in which the network cable accepts electrical signals from the interface, and contains a fiber optic transciever.

[Brian] was able to get the 3 computers networked for just $120, with parts sourced from eBay. It’s an approach that doesn’t scale well; larger setups would be much better served by using a switch and a less zany network topology. But for [Brian], it works just fine, and allows his NAS to outperform a 15,000 RPM server hard disk as far as read rates go.

If you’re curious about improving your own network performance, it might pay to look at your cables first – things are not always as they seem.