Archive

Category Archives for "Networking"

Worth Reading: DNS query name minimization

One new thing you need to add your DNS security policies is “query name minimizations” (RFC 7816). I thought I’d mention it since many haven’t heard about it. Right now, when DNS resolvers lookup a name like “www.example.com.”, they send the entire name to the root server (like a.root-servers.net.). When it gets back the answer to the .com DNS server a.gtld-servers.net), it then resends the full “www.example.com” query to that server. This is obviously unnecessary. The first query should be just .com. to the root server, then example.com. to the next server — the minimal amount needed for each query, not the full query. —Robert Graham @ Errata Security

The post Worth Reading: DNS query name minimization appeared first on rule 11 reader.

Securing Bitcoins with TREZOR

TREZOR is a hard wallet for securely storing crypto assets such as Bitcoin, Ethereum, and Litecoin. Protection mechanisms like a mnemonic recovery seed, PIN, and encryption passphrase safeguard your assets (private keys) by requiring your physical interaction in order to make transactions. For those crypto noobies, I think it’s easiest to describe the TREZOR functionality […]

The post Securing Bitcoins with TREZOR appeared first on Overlaid.

App Highlight: Hardenize

Hardenize is a comprehensive security tool that continuously monitors the security and configuration of your domain name, email, and website. Ivan Ristić, the author of Hardenize, gave a demo of his app at our Cloudflare London HQ.



Do you know how secure your site is? View a Hardenize report on your website by clicking this button:



Interested in sharing a demo of your app at a meetup? We can help coordinate. Drop a line to [email protected].

Broken packets: IP fragmentation is flawed

As opposed to the public telephone network, the internet has a Packet Switched design. But just how big can these packets be?

CC BY 2.0 image by ajmexico, inspired by

This is an old question and the IPv4 RFCs answer it pretty clearly. The idea was to split the problem into two separate concerns:

  • What is the maximum packet size that can be handled by operating systems on both ends?

  • What is the maximum permitted datagram size that can be safely pushed through the physical connections between the hosts?

When a packet is too big for a physical link, an intermediate router might chop it into multiple smaller datagrams in order to make it fit. This process is called "forward" IP fragmentation and the smaller datagrams are called IP fragments1.

Image by Geoff Huston, reproduced with permission

The IPv4 specification defines the minimal requirements. From the RFC791:

Every internet destination must be able to receive a datagram
of 576 octets either in one piece or in fragments to
be reassembled. [...]

Every internet module must be able to forward a datagram of 68
octets without further fragmentation. [...]

The first value - Continue reading

Got my number!

After a week of waiting (why this is taking so long? this wasn’t a particularly pleasant week), I finally got my number.

Brand new JNCIE-DC #31 !!!

The main note about the lab – time management is the most important thing on the exam. Don’t rush to the keyboard, read and understand all the tasks and it’s interdependencies. Have a plan regarding order of tasks – not all tasks can be completed in order in which they written. Don’t be affraid to skip some tasks if it takes a long time.

I am quite pleased with the level of my preparation for the lab – there were no unexpected or incomprehensible tasks. General feeling about JNCIE-DC lab – this is interesting, pretty complex but fair exam. Lot of tasks on various themes, I think all themes from blueprint are covered in the lab in some ways.

As the proctor told me, the main difficulty of this exam is that it’s something new, and people are afraid of a new and unexpected. I want to tell you – don’t be afraid! If you’re interested in learning a Juniper way of building Data Center networks, and also want to earn one more pretty Continue reading

Worth Reading: Supporting new DNS RR types

The Domain Name System has always been intended to be extensible. The original spec in the 1980s had about a dozen resource record types (RRTYPEs), and since then people have invented many more so now there are about 65 different RRTYPEs. But if you look at most DNS zones, you’ll only see a handful of types, NS, A, AAAA, MX, TXT, and maybe SRV. Why? A lot of the other types are arcane or obsolete, but there are plenty that are useful. Moreover, new designs like DKIM, DMARC, and notoriously SPF have reused TXT records rather than defining new types of their own. Why? It’s the provisioning crudware. —John Levine @ CircleID

The post Worth Reading: Supporting new DNS RR types appeared first on rule 11 reader.

Automating Documentation

Tedium is the enemy of productivity. The fastest way for a task to not be done is to make it long, boring, and somewhat complicated. People who feel that something is tedious or repetitive are the ones more likely to marginalize a task. And I think I speak for the entire industry when I say that there is no task more tedious and boring than documentation. So how can we fix it?

Tell Me What You Did

I’m not a huge fan of documentation. When I decide on a plan of action, I rarely write it down step-by-step unless I’m trying to train someone. Even then, it looks more like notes with keywords instead of a narrative to follow. It’s a habit that has been borne out of years of firefighting in networks and calls to “do it faster”. The essential items of a task are refined and reduced until all that remains is the work and none of the ancillary items, like documentation.

Based on my previous life as a network engineer, I can honestly say that I’m not alone in this either. My old company made lots of money doing network discovery engagements. Sometimes these came because the Continue reading

Microsoft acquires cloud-based HPC developer

Microsoft pulled off a big get with its acquisition of Cycle Computing, the developer of a suite of high-performance computing (HPC) services called CycleCloud for cloud orchestration, provisioning and data management in the cloud.You may not know its name but Cycle Computing is actually a major player. In 2012, it helped Amazon create the first massive cloud-based supercomputer, spanning 51,000 cores. For just one hour of run time, the bill was $5,000.+ Also on Network World: Azure Stack: Microsoft’s private-cloud platform and what IT pros need to know about it + In 2013, Cycle Computing hit its biggest cloud run, creating a cluster of 156,314 cores with a theoretical peak speed of 1.21 petaflops that ran for 18 hours and spanned Amazon data centers around the world. The bill for that monstrosity was $33,000. To read this article in full or to leave a comment, please click here

Microsoft acquires cloud-based HPC developer

Microsoft pulled off a big get with its acquisition of Cycle Computing, the developer of a suite of high-performance computing (HPC) services called CycleCloud for cloud orchestration, provisioning and data management in the cloud.You may not know its name but Cycle Computing is actually a major player. In 2012, it helped Amazon create the first massive cloud-based supercomputer, spanning 51,000 cores. For just one hour of run time, the bill was $5,000.+ Also on Network World: Azure Stack: Microsoft’s private-cloud platform and what IT pros need to know about it + In 2013, Cycle Computing hit its biggest cloud run, creating a cluster of 156,314 cores with a theoretical peak speed of 1.21 petaflops that ran for 18 hours and spanned Amazon data centers around the world. The bill for that monstrosity was $33,000. To read this article in full or to leave a comment, please click here

Microsoft acquires cloud-based HPC developer

Microsoft pulled off a big get with its acquisition of Cycle Computing, the developer of a suite of high-performance computing (HPC) services called CycleCloud for cloud orchestration, provisioning and data management in the cloud.You may not know its name but Cycle Computing is actually a major player. In 2012, it helped Amazon create the first massive cloud-based supercomputer, spanning 51,000 cores. For just one hour of run time, the bill was $5,000.+ Also on Network World: Azure Stack: Microsoft’s private-cloud platform and what IT pros need to know about it + In 2013, Cycle Computing hit its biggest cloud run, creating a cluster of 156,314 cores with a theoretical peak speed of 1.21 petaflops that ran for 18 hours and spanned Amazon data centers around the world. The bill for that monstrosity was $33,000. To read this article in full or to leave a comment, please click here

Microsoft acquires cloud-based HPC developer

Microsoft pulled off a big get with its acquisition of Cycle Computing, the developer of a suite of high-performance computing (HPC) services called CycleCloud for cloud orchestration, provisioning and data management in the cloud.You may not know its name but Cycle Computing is actually a major player. In 2012, it helped Amazon create the first massive cloud-based supercomputer, spanning 51,000 cores. For just one hour of run time, the bill was $5,000.+ Also on Network World: Azure Stack: Microsoft’s private-cloud platform and what IT pros need to know about it + In 2013, Cycle Computing hit its biggest cloud run, creating a cluster of 156,314 cores with a theoretical peak speed of 1.21 petaflops that ran for 18 hours and spanned Amazon data centers around the world. The bill for that monstrosity was $33,000. To read this article in full or to leave a comment, please click here

1 … 1,557 1,558 1,559 1,560 1,561 … 3,346