A few months ago VMware launched NSX version 6.2, and I asked my friend Anthony Burke to tell us more about the new features. Not surprisingly, we quickly started talking about troubleshooting, routing problems, and finished with route-health-injection done with a Python script. The end result: Episode 50 of Software Gone Wild. Enjoy!
Since spending quality time with complexity theory when writing Navigating Network Complexity, I’ve started seeing the three sided complexity problem crop up all over the place. Remember this? Fast, high quality, cheap: choose two. We face this problem in a number of ways in network design. A recent (last year) paper by researchers from University of Louvain, ETH Zürich and Princeton have figured out how to engineer traffic in a straight IP network (no MPLS) by injecting false nodes into the shortest path tree. You can read the paper here, and listen to Ivan’s podcast with one of the authors here.
What’s interesting to me is the direct tradeoff this paper represents between the amount of state in the control plane and optimal traffic flow through the network. Adding state does, in fact, allow you to optimize traffic flow—at the cost of calculating the state and injecting it into your control plane (in this case OSPF). This state must be carried through the network, increasing the amount of state in the network, and it must change as traffic flows change, increasing the speed at which the state changes in the network. Finally, this idea opens up a new interaction surface Continue reading
No doubt you are spending big bucks on enterprise storage, and the vendors want to keep it that way.
For a few years now I have used the term “nerd knobs” to describe a certain class of features implemented in networking products. This may have created the (mistaken) impression that nerd knobs are part of the IT hero culture. From now on I’m calling them “Wanker Knobs.” In most cases, wanker knobs are for […]
The post Nerd Knobs? No, It’s Wanker Knobs appeared first on EtherealMind.
Research reveals how some drivers for enterprise SDN deployment have shifted while others remain constant.
Learn from the experts how IoT will affect you, and how your company can benefit from its intelligence.
The Cloonix network simulator has been updated to version 29, which adds the ability to save network simulation topologies and node configurations to a directory.
Users may save a network topology and all node configurations to a directory of their choice. They may also load saved topologies into Cloonix so they can restore a network scenario they previously created. The save function of Cloonix v29 supports copy-on-write filesystems and also allows users to save the full filesystems of nodes, if they wish.
This post will work through a detailed tutorial showing how to save, load, and re-save topologies and node configurations using the Cloonix GUI or command-line interface.
In this tutorial we will show three ways Cloonix may be used to save filesystems and network topologies:
In part one, we saw how AES can be used to encrypt sensitive data so that it can be retrieved only by using an encryption key. The problem with this approach is that everyone who needs access to the data must have a copy of the key. If any one of these copies becomes compromised, the entire database must be re-encrypted using a new key, and the new key must be distributed securely to all parties involved. In this article, we'll see how symmetric encryption can be combined with asymmetric cryptography (namely RSA) to create a hybrid cryptosystem.
Let's begin by encrypting some data using AES as we did in part one. First we pad our plaintext's length to a multiple of 16 using null bytes, then generate a 256-bit encryption key and a 128-bit IV, and finally encrypt it with CFB-mode AES to generate a string of ciphertext.
>>> from Crypto.Cipher import AES >>> import os >>> plaintext = "Operation Neptune will launch on June 6th" >>> plaintext += (16 - len(plaintext) % 16) * chr(0) >>> encryption_key = os.urandom(32) >>> iv = os.urandom(16) >>> cipher = AES.new(encryption_key, AES.MODE_CFB, iv) >>> ciphertext = Continue reading
In part one, we saw how AES can be used to encrypt sensitive data so that it can be retrieved only by using an encryption key. The problem with this approach is that everyone who needs access to the data must have a copy of the key. If any one of these copies becomes compromised, the entire database must be re-encrypted using a new key, and the new key must be distributed securely to all parties involved. In this article, we'll see how symmetric encryption can be combined with asymmetric cryptography (namely RSA) to create a hybrid cryptosystem.
Let's begin by encrypting some data using AES as we did in part one. First we pad our plaintext's length to a multiple of 16 using null bytes, then generate a 256-bit encryption key and a 128-bit IV, and finally encrypt it with CFB-mode AES to generate a string of ciphertext.
>>> from Crypto.Cipher import AES >>> import os >>> plaintext = "Operation Neptune will launch on June 6th" >>> plaintext += (16 - len(plaintext) % 16) * chr(0) >>> encryption_key = os.urandom(32) >>> iv = os.urandom(16) >>> cipher = AES.new(encryption_key, AES.MODE_CFB, iv) >>> ciphertext = Continue reading
In part one, we saw how AES can be used to encrypt sensitive data so that it can be retrieved only by using an encryption key. The problem with this approach is that everyone who needs access to the data must have a copy of the key. If any one of these copies becomes compromised, the entire database must be re-encrypted using a new key, and the new key must be distributed securely to all parties involved. In this article, we'll see how symmetric encryption can be combined with asymmetric cryptography (namely RSA) to create a hybrid cryptosystem.
Let's begin by encrypting some data using AES as we did in part one. First we pad our plaintext's length to a multiple of 16 using null bytes, then generate a 256-bit encryption key and a 128-bit IV, and finally encrypt it with CFB-mode AES to generate a string of ciphertext.
>>> from Crypto.Cipher import AES >>> import os >>> plaintext = "Operation Neptune will launch on June 6th" >>> plaintext += (16 - len(plaintext) % 16) * chr(0) >>> encryption_key = os.urandom(32) >>> iv = os.urandom(16) >>> cipher = AES.new(encryption_key, AES.MODE_CFB, iv) >>> ciphertext = Continue reading
Several months ago we started hearing occasional reports from .NET developers that they were having trouble maintaining HTTPS sessions with one of our customer’s websites. Establishing connections worked just fine but they would periodically get disconnected, resulting in an exception that crashed their application. Around the same time, we also started hearing reports that two other Microsoft products—Internet Explorer and its heir-apparent, Edge—were also having trouble with our edge.
Just a few weeks prior, we had updated our handling of TLS session tickets to be more performant and more secure. We suspected these improvements were the trigger and focused our investigation there. What we learned was that the problem ran much deeper than .NET or IE. It went all the way down to the SChannel security package, which provides TLS functionality for a vast array of Microsoft applications.
Before diving into the story further, however, it’s helpful to understand exactly what TLS session tickets are, how they’re beneficial to HTTPS, and what optimizations CloudFlare does to use them at scale. (If you’d like to skip over the primer and jump right to the punchline, go ahead and click here.)
First introduced in Continue reading
OSPF LSA (link state advertisements) are used to create a logical network topology. But Why we have 11 different LSAs ? What are their purposes ? Most important questions many time is not asked by the engineers thus you can’t find many places on the Internet which provides these answers. The reason of having 11 […]
The post OSPF LSA Types appeared first on Cisco Network Design and Architecture | CCDE Bootcamp | orhanergun.net.
OSPF LSA (link state advertisements) are used to create a logical network topology. But Why we have 11 different LSAs ? What are their purposes ? Most important questions many time is not asked by the engineers thus you can’t find many places on the Internet which provides these answers. The reason of having 11 […]
The post OSPF LSA Types appeared first on Orhanergun.
An early teaser for the MWC cage match against Nokia.