After the initial onslaught of SDN washing, four distinct approaches to SDN have started to emerge, from centralized control plane architectures to smart reuse of existing protocols.
As always, each approach has its benefits and drawbacks, and there’s no universally best solution. You just got four more (somewhat immature) tools in your toolbox. And now for the details.
Read more ...Network monitoring is one of our most requested topics on Packet Pushers, and this week we take on open source monitoring solutions. Why open source? Because commercial NMS solutions are all over the place in functionality and price. So, if it’s possible to put a solid NMS in place based on open source, then it’s […]
The post Show 205 – Open Source Network Monitoring with OMDistro.org appeared first on Packet Pushers Podcast and was written by Ethan Banks.
Legacy networking vendors have often declared that they do not build “boxes” but actually build “systems and architectures”. I have tried to understand what that really means. Undoubtedly, new applications on the Internet have evolved and now depend on a modern infrastructure that outlives any particular static workload or physical machine. Indeed, at Arista, we along with our customers are looking at a technology evolution that goes beyond individual components to a universal cloud architecture.
Building a “best of breed” product is a vital foundation to building a good system. Typical metrics may include feeds and speeds such as latency, power, port density (non-blocking), fabric capacity, throughput and scale combined with a feature-rich network operating system. Examples of this include Cisco’s routers and Catalyst switches (with IOS) in the 1990s, F5’s Big IP and Splunk’s data analytics in the past decade, or even more recently, Arista’s 7000 series Leaf-Spine-Spline products. Vendors with breakthrough products are pioneers and thought-leaders in their markets and often establish trends rather than follow them. Sustained differentiation beyond point features is a common theme. Such products are disruptive in nature, bringing critical business benefits and reducing capex spend within Continue reading
At CloudFlare, We use Go for a variety of services and applications. In this blog post, We're going to take a deep dive into some of the technical intricacies of Go.
One of the more important features of Go is goroutines. They are cheap, cooperatively scheduled threads of execution that are used for a variety of operations, like timeouts, generators and racing multiple backends against each other. To make goroutines suitable for as many tasks as possible, we have to make sure that each goroutine takes up the least amount of memory, but also have people be able to start them up with a minimal amount of configuration.
To achieve this, Go manages stacks in way that behaves like any other language, but is quite different in how they're implemented.
Before we look at Go, let's look at how stacks are managed in a traditional language like C.
When you start up a thread in C, the standard library is responsible for allocating a block of memory to be used as that thread's stack. It will allocate this block, tell the kernel where it is and let the kernel handle the execution of the thread. Continue reading
A friend of mine — Tony P to be exact — recently talked me into reading up on UML. I hadn’t worked a lot with modeling languages in a serious way before, but I took the bait and read UML Distilled (Safari Amazon). Okay — this is actually interesting stuff. First, a short review of the book itself.
There are, according to the author, two sorts of UML models. The one advocated here is sketchup, which is used to outline a process or the relationship between various components. There is a stricter version of UML that can actually be compiled into software, but I immediately attached the PowerPoint compiler to this in my head (right or wrong, there’s something about moving from a model to a product without anything in the middle that just doesn’t seem right to me — maybe I’m just an old fogy or something). The progress of the book is useful, moving from the basic concept of modeling languages, a history of the UML, and finally through several constructs within the UML. The author attempts to take you through enough constructs to get you to the point of being able to use the UML Continue reading
I often find myself viewing HTTP headers (request and response) at the ‘client side’, which are often much quicker (and safer) than decrypting SSL/TLS traffic on a load balancer/ADC. With the use of SSL/TLS growing rapidly even within private networks and the inability to decrypt PFS/DHE protected traffic, this can often be the only way to troubleshoot. The reasons I […]
The post Viewing HTTP Headers Using Browser Developer Tools appeared first on Packet Pushers Podcast and was written by Steven Iveson.
I’ve had network monitoring systems on my mind recently as we’ve been looking to determine the right specification for a number of fiber taps and aggregation devices so that we can fulfill the needs of both the security teams (for … Continue reading
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The cloud is one of those technology trends that seems to be perpetually on the cusp of becoming ubiquitous. But if recent analyst reports are any indication, cloud’s breakthrough moment is imminent. Late last year, Gartner predicted that in 2016, the bulk of new IT spend would shift to the public cloud, and that by the end of 2017, nearly half of all enterprises will have hybrid cloud deployments.
But if cloud has been around for so long, why will it take so long for cloud to become the dominant source of IT spend?
The determinant for most change is the underlying psychology that drives individuals and organizations. The IT industry as a whole has been underpinned by a deep-seeded need for control. The reason that most companies keep expertise in-house is that they want to maintain control—over their data, over the integration with their business workflows, over their schedules, and over their spend.
Of course control is under constant attack by cost. While traffic is booming, IT spend in most organizations continues to trend flat to down. This means that organizations need to constantly provide more compute resources, more storage, and faster interconnect while working with Continue reading
If you care about building your own SDN skills, SDN certifications should matter to you, at least for the purpose of figuring out what to study (an argument I’ve made in an earlier post.) Since that time, the SDN world has seen several updates to vendor SDN certifications. (I’m also hopeful that we’ll see a few more at the upcoming Interop New York show towards the end of September.) Today’s post summarizes those that merit a look, at least for the purposes of figuring out what you might want to learn to retool for an SDN world.
Here’s a quick list of surprises and other goodies from this latest scan of the state of the art:
Dig into the rest of the post for more details!
I spent last Tuesday in Bern attending the SIGS DC Day Event, and came back home extremely pleasantly surprised. The conference was nice and cozy, giving everyone plenty of opportunities to chat about data center technical challenges (thanks for all the wonderful conversations we had – you know who you are!).
Having the opportunity to meet fellow networking engineers and compare notes is great, but it’s even better to combine that with new knowledge, and that’s where the event really excelled.
Read more ...
Breathin' so free on non-extradition soil now. Breakup with USA is done now.
— Andrew Auernheimer (@rabite) September 14, 2014IP NAT is a very common configuration. One of the challenges that sometimes surfaces is the need for internal hosts to connect to the public address of a locally hosted server. Anyone who has tried to configure something like the following has likely faced this issue.
In this example, the top of the diagram represents the outside (Internet, ISP, or External Server), the left represents the DMZ area, and the bottom represents the inside. The goal is to enable dynamic port address translation for internal hosts and static port address translation for the host or hosts found in the DMZ area.
This configuration is fairly straightforward and typically covered in the CCNA curriculum. This includes identifying each interface as inside or outside and configuring the appropriate nat statements.
interface FastEthernet1/0 description To INSIDE ip address 192.168.1.1 255.255.255.0 ip nat inside ! interface FastEthernet1/1 description To ACME WWW ip address 192.168.2.1 255.255.255.0 ip nat inside ! interface FastEthernet1/2 description To OUTSIDE ip address 192.0.2.100 255.255.255.0 ip nat outside ! ip nat inside source list 1 interface FastEthernet1/2 overload ip nat inside source static tcp 192.168. Continue reading
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| CC BY-NC-ND 2.0 licensed photo by smif Needs deduplication |
The Sourcefire NGIPS/NGFW solution is a way to quickly get some interesting information about traffic on a network. One of the things I like about the solution is that actionable information is almost immediately available after deployment.
There are five deployment modes for a Sourcefire Firepower appliance:
Passive and inline modes are the two deployment options for the Virtual versions of the Firepower appliances. Inline mode provides significant advantages over simple passive monitoring. Inline mode allows the appliance to block offending traffic or communications that violates the configured policy. Following the installation guide is straightforward and should allow a security engineer to quickly get this solution up and running.
The first time I ran through this process, I couldn’t get traffic to flow through the inline appliance. After struggling a while, I reconfigured the device into passive mode and spanned some traffic over to it. At first I didn’t see any statistics. After realizing that I also needed to configure VMWare to accept promiscuous mode, I quickly started getting interesting information in the Firesight dashboard.
At this point, a thought occurred to me. What if the Firepower appliance had no layer 2 hooks and forwarded traffic that blindly Continue reading