CloudFlare “Interview Questions”

For quite some time we've been grilling our candidates about dirty corners of TCP/IP stack. Every engineer here must prove his/her comprehensive understanding of the full network stack. For example: what are the differences in checksumming algorithms between IPv4 and IPv6 stacks?

I'm joking of course, but in the spirit of the old TCP/IP pub game I want to share some of the amusing TCP/IP quirks I've bumped into over the last few months while working on CloudFlare's automatic attack mitigation systems.

CC BY-SA 2.0 image by Daan Berg

Don't worry if you don't know the correct answer: you may always come up with a funny one!

Some of the questions are fairly obvious, some don't have a direct answer and are supposed to provoke a longer discussion. The goal is to encourage our readers to review the dusty RFCs, get interested in the inner workings of the network stack and generally spread the knowledge about the protocols we rely on so much.

Don't forget to add a comment below if you want to share a response!

You think you know all about TCP/IP? Let's find out.

Archaeology

1) What is the lowest TCP port number?

2) The TCP Continue reading

Geneve

One of the various problems we face in the data networking world is the absolute plethora of tunneling technologies we have available. Going way back to the beginning, there was SNA, GRE, IP-in-IP, and a host of others. In the midterm was have MPLS (though some will argue this isn’t a tunneling protocol — but […]

Author information

Russ White

Principal Engineer at Ericsson

Russ White has scribbled a basket of books, penned a plethora of patents, written a raft of RFCs, taught a trencher of classes, nibbled and noodled at a lot of networks, and done a lot of other stuff you either already know about — or don't really care about. You can find Russ at 'net Work, the Internet Protocol Journal, LinkedIn, and his author page on Amazon.
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The post Geneve appeared first on Packet Pushers Podcast and was written by Russ White.

Old-school anti-virus vendors learn new tricks

In an era when businesses are scrambling to defend against sophisticated advanced persistent threats, old school anti-virus may seem like a relic. But traditional anti-virus companies are changing with the times, delivering defense-in-depth for a BYOD world.In this review, we looked at products from seven of the original anti-virus vendors, each dating back to at least the 1990s: AVG, ESET, Kaspersky, McAfee, Symantec, Panda Software and Trend Micro. We focused on ease of installation and management, ease of use, plus the protection each suite offered beyond traditional signature-based anti-virus. Special emphasis was placed on the software’s ability to also protect mobile devices running both iOS and Android. (Read an analysis of the antivirus market.)To read this article in full or to leave a comment, please click here(Insider Story)

New products of the week 05.11.15

New products of the weekOur roundup of intriguing new products. Read how to submit an entry to Network World's products of the week slideshow.Barracuda NG Firewall on AzureKey features – Barracuda NG Firewall now supports new routing functionality in Azure with User Defined Routes and also works with ExpressRoute providing additional security, redundancy, and application aware traffic routing. More info.To read this article in full or to leave a comment, please click here

New products of the week 05.11.15

New products of the weekOur roundup of intriguing new products. Read how to submit an entry to Network World's products of the week slideshow.Barracuda NG Firewall on AzureKey features – Barracuda NG Firewall now supports new routing functionality in Azure with User Defined Routes and also works with ExpressRoute providing additional security, redundancy, and application aware traffic routing. More info.To read this article in full or to leave a comment, please click here

Chinese smartphone market shows rare shipment decline

The world’s largest smartphone market, China, isn’t so hungry for the products anymore.First quarter smartphone shipments there dropped by 4 percent year over year, according to research firm IDC. It’s the first time in six years that China’s smartphone market has contracted, signifying that the country’s appetite for the handsets is reaching its limit.The number of shipments to China was still high, at 98.8 million units. IDC expects the market to remain flat for the rest of the year. To drive future growth vendors in the country will have to convince existing users to upgrade to newer phones, IDC said.To read this article in full or to leave a comment, please click here

BGP AIGP

In this post we will look at something which is relatively new but not as cool as my previous post on Segment Routing. We will take a look at a new BGP feature called “Accumulated IGP, metric of path to prefix” (RFC 7311 AIGP)  which is an optional non-transitive attribute . A new AIGP TLV was created for this which contains […]

Author information

Diptanshu Singh

Diptanshu Singh

Diptanshu Singh,(3xCCIE,CCDE) is a Sr. Engineer mostly focused on service providers , data center and security. He is a network enthusiast passionate about network technologies so not only is it his profession, but something of a hobby as well.
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The post BGP AIGP appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.

Do We Need Network Programmability?

Jsicuran left this comment on my You Must Understand the Fundamentals to Be Successful blog post:

I just went through some Cisco webinar where they were showcasing the use of NX-OS API and Python to add a VLAN. I do some Python myself and have used that API for some simple DevOps-like uses, but for the most part if you are an enterprise and use Prime DCIM to add VLANs, why should you go through the coding process?

It obviously depends on where you are in your IT automation journey.

Read more ...

IBM’s flexible Power servers can take on cloud, databases

IBM is building slimmer versions of its Power hardware—used by its Watson supercomputer—to run complex database applications as well as simpler Web-based ones.IBM has designed its latest Power servers for social networking, search engines and cloud storage, as computing moves from PCs to mobile devices. Beyond the cloud, the new servers with Power8 chips also have the horsepower to handle more complex applications like databases and analytics.The multipurpose servers include the four-socket Power E850, which can handle private, public and hybrid clouds, and in-memory database applications. The more powerful Power E880 is for large-scale database and cloud implementations.To read this article in full or to leave a comment, please click here

Apple focuses on making supply chain in China more green

Apple plans to make its supply chain in China greener as a way to cutdown on carbon emissions from its product manufacturing, the company announced on Monday.The U.S. tech giant has already been making its offices and data centers more environmentally friendly, but wants to extend those efforts to its suppliers in China, Apple CEO Tim Cook said in a statement. Although the transition to more greener manufacturing will take years, Cook said it is important work that needs to be done.In China, Many Apple products, including the iPhone and iPad, are assembled in large factories run by Foxconn Technology Group and by other large contract manufacturers.To read this article in full or to leave a comment, please click here

OSPF Path Selection Challenge

I had an interesting question come across my desk today which involved a very common area of confusion in OSPF routing logic, and now I’m posing this question to you as a challenge!

The first person to answer correctly will get free attendance to our upcoming CCIE Routing & Switching Lab Cram Session, which runs the week of June 1st 2015, as well as a free copy of the class in download format after it is complete.  The question is as follows:

Given the below topology, where R4 mutually redistributes between EIGRP and OSPF, which path(s) will R1 choose to reach the network 5.5.5.5/32, and why?

Bonus Questions:

  • What will R2′s path selection to 5.5.5.5/32 be, and why?
  • What will R3′s path selection to 5.5.5.5/32 be, and why?
  • Assume R3′s link to R1 is lost.  Does this affect R1′s path selection to 5.5.5.5/32? If so, how?

Tomorrow I’ll be post topology and config files for CSR1000v, VIRL, GNS3, etc. so you can try this out yourself, but first answer the question without seeing the result and see if your expected result matches the actual result!

 

Good luck everyone!

Running Docker Machine on Digital Ocean

Continuing the series on cloud provider examples using Docker machine, up next is Digital Ocean. As with the other posts here is a diagram of how I view Docker Machine usage. For those who don’t have an account already, you can sign get $10 credit with the following link. When you sign up it requires a credit card that won’t ... The post Running Docker Machine on Digital Ocean appeared first on NetworkStatic | Brent Salisbury's Blog.

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iPhone 7 rumor rollup: Your brain on iPhone 7 and plastic survives

Given that Apple sold 61 million iPhones in its most recent quarter and that the iPhone 6 Plus now dominates the U.S. market for phablets with 5.5-inch screens or bigger, you might think Apple could coast for a spell, and that rumors of the iPhone 6S or iPhone 7 would be overkill. But no, the rumor mills cranks along.Your Brain on iPhone 7 Noka Productions Some people are really into the iPhone, and the filmmakers at Noka Productions think the iPhone 7 could literally be into you.To read this article in full or to leave a comment, please click here

Network Break 37

Take a Network Break! Grab a coffee, a doughnut and then join us for an analysis of the latest IT news, vendor moves and new product announcements. We’ll separate the signal from the noise--or at least make some noise of our own. Sponsored by Viptela and Open Networking Summit 2015.

Author information

Greg Ferro

Greg Ferro is a Network Engineer/Architect, mostly focussed on Data Centre, Security Infrastructure, and recently Virtualization. He has over 20 years in IT, in wide range of employers working as a freelance consultant including Finance, Service Providers and Online Companies. He is CCIE#6920 and has a few ideas about the world, but not enough to really count.

He is a host on the Packet Pushers Podcast, blogger at EtherealMind.com and on Twitter @etherealmind and Google Plus.

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The post Network Break 37 appeared first on Packet Pushers Podcast and was written by Greg Ferro.

10 Examples of how to get Docker Container IP Address

One thing that is so much fun about the need virtualization paradigm we are heading towards is that in the age of “software defined”, the flexibility of how to do things with infra are much more like programming then working with highly opinionated traditional infrastructure. Along that thread, here are 10 different ways to get a container or docker-machine address ... The post 10 Examples of how to get Docker Container IP Address appeared first on NetworkStatic | Brent...

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Citizens of Tech 002 – Electric Space Trains

Happy 25th, Hubble. Fold my keyboard. Trains didn't (and don't) suck. Batteries are sexy again. Puking in your VR helmet. FM radio on Deathwatch. These and more stories on Citizens of Tech #2!

Author information

Ethan Banks

Co-host at Packet Pushers

Ethan Banks, CCIE #20655, has been managing networks for higher ed, government, financials and high tech since 1995. Ethan co-hosts the Packet Pushers Podcast, which has seen over 3M downloads and reaches over 10K listeners. With whatever time is left, Ethan writes for fun & profit, studies for certifications, and enjoys science fiction. @ecbanks
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The post Citizens of Tech 002 – Electric Space Trains appeared first on Packet Pushers Podcast and was written by Ethan Banks.

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