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Category Archives for "Networking"

A Deeper Dive Into Public DNS Resolver Quad9

There are plenty of public DNS resolvers. The best known was Google Public DNS i.e. 8.8.8.8 and 8.8.4.4 for IPv4 and 2001:4860:4860::8888 and 2001:4860:4860::8844 for IPv6. But there are a few other options available now, each with different policies and technical features.

Two new Public DNS resolvers were recently launched. Quad9 (launched Nov 2017) and 1dot1dot1dot1 (launched Apr 2018). We have already covered 1.1.1.1 in detail in a recent blog. So let’s talk about Quad9 (9.9.9.9).

The Global Cyber Alliance (GCA), an organization founded by a partnership of law enforcement (New York County District Attorney and City of London Police) and research (Center for Internet Security – CIS) organizations focused on combating systemic cyber risk in real, measurable ways, partnered with IBM and Packet Clearing House (PCH) to launch a Global Public Recursive DNS Resolver Service. Quad9 protects users from accessing known malicious websites, leveraging threat intelligence from multiple industry leaders; it currently blocks up to two million threats per day.

A handy little infographic on the Quad9 website helps show how it works. Essentially, you set up Quad 9 as your Continue reading

Show 397: The Future Of Networking With Peter Wohlers

Our next installment of the Future Of Networking series brings Peter Wohlers to the podcast.

Way back in the early history of Packet Pushers, we received a presentation from Peter when he worked at Force10 as part of a Tech Field Day event. It was blunt, knowledgeable, cynical and nerd-funny.

Today Peter is VP of Engineering at a large CDN. I invited him to come on talk about the current and future state of the industry.

We discuss the effect of cloud computing on the networking industry and its impact on skills and careers, the early hype around SDN and where it stands today, how much skill you really need in coding, the rise of APIs in networking, and a passionate debate about whether different networks are actually all that unique.

Show Links:

TFD Bonus 3 Peter Wohlers of Force10 Presents to Tech Field Day San Jose 09/16/2010 – Packet Pushers

The post Show 397: The Future Of Networking With Peter Wohlers appeared first on Packet Pushers.

Leading Uruguayan Students to Thrive in the Future Economy

Current researches show that children are exposed to both increased risks and increased opportunities when accessing  the Internet and using apps and social media. The UNICEF’s “Children in a Digital World” 2017 report takes a comprehensive look at the different ways digital technology affects children. It is critical that children have necessary training in digital literacy to acquire the skills to minimize risks and to confidently navigate the web to maximize their opportunities. Evidence suggests that technology has benefits where positive human forces for learning are already in place.

The University of the Republic in partnership with the Internet Society Uruguay Chapter and the financial support of the Beyond the Net Funding Programme has taken significant steps to help children and teenagers to develop digital skills in a creative and innovative way in three of the nineteen segments in which Uruguay is politically divided, Paysandú, Rivera, and Salto. Their project  Flor de Ceibo Conecta2 aims to train young people from disadvantaged communities using digital resources in creative and challenging learning classes to help them improve their everyday lives and expand their chances for a better future.

María Julia Morales González, project manager and professor at the Department of Sociology and Continue reading

How to drop 10 million packets per second

How to drop 10 million packets per second

Internally our DDoS mitigation team is sometimes called "the packet droppers". When other teams build exciting products to do smart things with the traffic that passes through our network, we take joy in discovering novel ways of discarding it.

How to drop 10 million packets per second
CC BY-SA 2.0 image by Brian Evans

Being able to quickly discard packets is very important to withstand DDoS attacks.

Dropping packets hitting our servers, as simple as it sounds, can be done on multiple layers. Each technique has its advantages and limitations. In this blog post we'll review all the techniques we tried thus far.

Test bench

To illustrate the relative performance of the methods we'll show some numbers. The benchmarks are synthetic, so take the numbers with a grain of salt. We'll use one of our Intel servers, with a 10Gbps network card. The hardware details aren't too important, since the tests are prepared to show the operating system, not hardware, limitations.

Our testing setup is prepared as follows:

  • We transmit a large number of tiny UDP packets, reaching 14Mpps (millions packets per second).

  • This traffic is directed towards a single CPU on a target server.

  • We measure the number of packets handled by the kernel on that Continue reading

IDG Contributor Network: Identifying the Internet of Things – one device at a time

As IoT movement pervades every facet of our lives, the pace of innovation in this field continues to grow. We are seeing novel uses of this technology that are very cool – we are also seeing a lot of implementations that are downright silly! However, most if not all, of these are very impactful. As we have seen in the past with agriculture or healthcare, IoT is moving fast and is here to stay. However, this being a classic case of trying to run before we’ve learned how to walk, IoT device developers often leave out the core component of any connected service in today’s world – security.To read this article in full, please click here

초당 천만개의 패킷을 버리는 방법

초당 천만개의 패킷을 버리는 방법

This is a Korean translation of a prior post by Marek Majkowski.

사내에서 DDoS 대응팀은 종종 "패킷 버리는 사람들"이라 불립니다. 다른 팀이 우리 네트워크를 통해 지나가는 트래픽으로 스마트한 일을 하며 신나할 때 우리는 그걸 버리는 여러가지 방법을 찾아가며 즐거워 합니다.

초당 천만개의 패킷을 버리는 방법

CC BY-SA 2.0 image by Brian Evans

DDoS 공격을 견뎌내기 위해서는 빠르게 패킷을 버릴 수 있는 능력이 매우 중요합니다.

쉽게 들리겠지만 서버에 도달한 패킷을 버리는 것은 여러 단계에서 가능합니다. 각 기법은 장점과 한계점이 있습니다. 이 블로그 글에서는 지금까지 시도해 본 기법들을 모두 정리해 보도록 하겠습니다.

테스트 벤치마크

각 기법의 상대적인 성능을 시각화하기 위해서 먼저 숫자를 볼 것입니다. 벤치마크는 합성 테스트이므로 실제 숫자와는 일부 차이가 있을 수 있습니다. 테스트를 위해서는 10Gbps 네트워크 카드가 달린 인텔 서버를 사용할 것입니다. 하드웨어가 아니라 운영체제의 한계를 보여주기 위한 테스트이므로 하드웨어의 상세 사항은 적지 않겠습니다.

테스트 설정은 다음과 같습니다:

  • 작은 크기의 UDP 패킷을 14Mpps (Mpps = 초당 백만 패킷) 에 도달하도록 대량으로 전송
  • 이 트래픽은 테스트 서버의 단일 CPU에 전달되도록 함
  • 단일 CPU에서 커널에 의해 처리되는 패킷의 개수를 측정

테스트는 사용자 공간 어플리케이션의 속도나 패킷 처리 속도를 최대화하려는 것이 아니라 커널의 병목 지점을 알고자 하는 것입니다.

합성 트래픽은 conntrack에 최대한의 부하를 주도록 준비되었습니다 - 임의의 소스 IP와 포트 필드를 사용합니다. tcpdump는 다음과 같이 Continue reading

Openswitch OPX Installation on Linux

We have recently covered installation of Openswitch OPS on Linux. Since the version 2.0, Openswitch OPS has transformed into to a completely new project, called Openswitch OPX Base. Similar to its predecessor, OpenSwitch OPX Base system also provides an abstraction of hardware devices of network switch platforms in a Linux OS environment. However, original Yocto OS has been replaced by an unmodified Linux kernel based on Debian Jessie distribution.

We can install OPX Base on a virtual machine, similar to installing OpenSwitch on hardware platforms. A virtual machine (VM) uses the same software binaries as those executed on S6000-ON devices. The main difference is that the low-level device drivers for the SAI and SDI libraries are replaced with the packages that support hardware simulation, and interact with the hardware simulation infrastructure.

A host machine running Openswitch OPX VM might be Windows, or Mac OS X with at least 8GB of RAM and 100GB available disk space, and Virtual Box installed. The virtual machine needs to have one network interface configured for the Management interface (eth0). The network adapter eth0 corresponds to the first adapter attached to the VM, e101-001-0 to the second adapter and so on, and e101-00N-1 to Continue reading

Openswitch OPX Installation on Linux

We have recently covered installation of Openswitch OPS on Linux. Since the version 2.0, Openswitch OPS has transformed into to a completely new project, called Openswitch OPX Base. Similar to its predecessor, OpenSwitch OPX Base system also provides an abstraction of hardware devices of network switch platforms in a Linux OS environment. However, original Yocto OS has been replaced by an unmodified Linux kernel based on Debian Jessie distribution.

We can install OPX Base on a virtual machine, similar to installing OpenSwitch on hardware platforms. A virtual machine (VM) uses the same software binaries as those executed on S6000-ON devices. The main difference is that the low-level device drivers for the SAI and SDI libraries are replaced with the packages that support hardware simulation, and interact with the hardware simulation infrastructure.

A host machine running Openswitch OPX VM might be Windows, or Mac OS X with at least 8GB of RAM and 100GB available disk space, and Virtual Box installed. The virtual machine needs to have one network interface configured for the Management interface (eth0). The network adapter eth0 corresponds to the first adapter attached to the VM, e101-001-0 to the second adapter and so on, and e101-00N-1 to Continue reading

Openswitch OPX Appliances

OpenSwitch OPX Base is an innovative operating system for network systems. It uses an unmodified Linux kernel and standard distribution to take advantage of rich ecosystem, and also provide flexibility in customizing your system according to your network needs.

Note: Openswitch OPX images are customized with my after install script  and they are ready for use in GNS3.

Openswitch OPX 2.3.2
https://drive.google.com/file/d/1Vdpjoz53R7Rx1HYi8KcEuRuNvQnMMn0f/view?usp=sharing
https://sourceforge.net/projects/gns-3/files/VirtualBox%20Appliances/OpenswitchOPX-2.3.2.zip
https://www.4shared.com/s/fQu2DUd9dca

Openswitch OPX Appliances

OpenSwitch OPX Base is an innovative operating system for network systems. It uses an unmodified Linux kernel and standard distribution to take advantage of rich ecosystem, and also provide flexibility in customizing your system according to your network needs.

Note: Openswitch OPX images are customized with my after install script  and they are ready for use in GNS3.

Openswitch OPX 2.3.2
https://drive.google.com/file/d/1Vdpjoz53R7Rx1HYi8KcEuRuNvQnMMn0f/view?usp=sharing
https://sourceforge.net/projects/gns-3/files/VirtualBox%20Appliances/OpenswitchOPX-2.3.2.zip
https://www.4shared.com/s/fQu2DUd9dca

Linux Shell Tips and Tricks

A collection of useful tips and tricks for the linux shell that I have stumbled across over the years. I'll keep updating this post as I come across something of value. I use bash, so these apply to bash unless noted otherwise but my work in other shells. cat The cat command can be...
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