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Category Archives for "Networking"

Using the Internet of Sound to transfer IoT data via speakers

Some kinds of data should be encoded onto an inaudible, near-ultrasound layer placed on top of normal, audible sounds — a process that could rapidly scale Internet of Things (IoT) adoption, says startup Trillbit.The company says that by doing that kind of overlay, any microphone and speaker is turned into a data-transfer device that then could be used for payments transfers, user authentication, and smart city applications such as digital locks.“There is no common universal protocol to connect Internet of Things,” Trillbit explains on its website. “Speakers [and microphones], which are already in place, and all around us” could perform connections.To read this article in full, please click here

Using the Internet of Sound to transfer IoT data via speakers

Some kinds of data should be encoded onto an inaudible, near-ultrasound layer placed on top of normal, audible sounds — a process that could rapidly scale Internet of Things (IoT) adoption, says startup Trillbit.The company says that by doing that kind of overlay, any microphone and speaker is turned into a data-transfer device that then could be used for payments transfers, user authentication, and smart city applications such as digital locks.“There is no common universal protocol to connect Internet of Things,” Trillbit explains on its website. “Speakers [and microphones], which are already in place, and all around us” could perform connections.To read this article in full, please click here

Interview: Active-Active Data Centers with VXLAN and EVPN

Christoph Jaggi asked me a few questions about using VXLAN with EVPN to build data center fabrics and data center interconnects (including active/active data centers). The German version was published on Inside-IT, here’s the English version.

He started with an obvious one:

What is an active-active data center and why would I want to use an active-active data center?

Numerous organizations have multiple data centers for load sharing or disaster recovery purposes. They could use one of their data centers and have the other(s) as warm or cold standby (active/backup setup) or use all data centers at the same time (active/active).

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Know your SCM_RIGHTS

As TLS 1.3 was ratified earlier this year, I was recollecting how we got started with it here at Cloudflare. We made the decision to be early adopters of TLS 1.3 a little over two years ago. It was a very important decision, and we took it very seriously.

It is no secret that Cloudflare uses nginx to handle user traffic. A little less known fact, is that we have several instances of nginx running. I won’t go into detail, but there is one instance whose job is to accept connections on port 443, and proxy them to another instance of nginx that actually handles the requests. It has pretty limited functionality otherwise. We fondly call it nginx-ssl.

Back then we were using OpenSSL for TLS and Crypto in nginx, but OpenSSL (and BoringSSL) had yet to announce a timeline for TLS 1.3 support, therefore we had to implement our own TLS 1.3 stack. Obviously we wanted an implementation that would not affect any customer or client that would not enable TLS 1.3. We also needed something that we could iterate on quickly, because the spec was very fluid back then, and also something Continue reading

Knowledge of the “Truths in Your Network” is KEY

I am a huge believer in “knowledge is key”.  Yeah… I know… just reading that statement you are probably saying “well yeah… duh”.

Of course knowledge is key… duh, Fish!  We know that!  We love knowledge.  We are knowledge seekers and we love to learn!  I mean… if we didn’t love learning and knowledge why would we be reading this?   Okay… got it.  You love knowledge.  You want to grow your knowledge.   I hear you.  You are basically saying… bring on the knowledge… max the setting!   Got it.

So you most likely extend that desire for knowledge to most of the areas in your life.

For example….

  • Buying a House:  When buying a house you want the knowledge you can get by hiring a subject matter expert to walk thru the entirety of the house and inspect it.  You want knowledge of the truths of that house.
  • Hiring a Financial Advisor: When hiring a financial advisor you just go and “bare all” in reference to your financial situation so they can review every nuance of it.   You want knowledge of the truths of your finances.

Let’s Continue reading

L4Drop: XDP DDoS Mitigations

L4Drop: XDP DDoS Mitigations

Efficient packet dropping is a key part of Cloudflare’s distributed denial of service (DDoS) attack mitigations. In this post, we introduce a new tool in our packet dropping arsenal: L4Drop.

L4Drop: XDP DDoS Mitigations
Public domain image by US Air Force

We've written about our DDoS mitigation pipeline extensively in the past, covering:

  • Gatebot: analyzes traffic hitting our edge and deploys DDoS mitigations matching suspect traffic.
  • bpftools: generates Berkeley Packet Filter (BPF) bytecode that matches packets based on DNS queries, p0F signatures, or tcpdump filters.
  • Iptables: matches traffic against the BPF generated by bpftools using the xt_bpf module, and drops it.
  • Floodgate: offloads work from iptables during big attacks that could otherwise overwhelm the kernel networking stack. Incoming traffic bypasses the kernel to go directly to a BPF interpreter in userspace, which efficiently drops packets matching the BPF rules produced by bpftools.

Both iptables and Floodgate send samples of received traffic to Gatebot for analysis, and filter incoming packets using rules generated by bpftools. This ends up looking something like this:

L4Drop: XDP DDoS Mitigations
Floodgate based DDoS mitigation pipeline

This pipeline has served us well, but a lot has changed since we implemented Floodgate. Our new Gen9 and ARM servers use different network Continue reading