Slicing and Dicing Flooding Domains (2)

The first post in this series is here.

Finally, let’s consider the first issue, the SPF run time. First, if you’ve been keeping track of the SPF run time in several locations throughout your network (you have been, right? Right?!? This should be a regular part of your documentation!), then you’ll know when there’s a big jump. But a big jump without a big change in some corresponding network design parameter (size of the network, etc.), isn’t a good reason to break up a flooding domain. Rather, it’s a good reason to go find out why the SPF run time changed, which means a good session of troubleshooting what’s probably an esoteric problem someplace.

Assume, however, that we’re not talking about a big jump. Rather, the SPF run time has been increasing over time, or you’re just looking at a particular network without any past history. My rule of thumb is to start really asking questions when the SPF run time gets to around 100ms. I don’t know where that number came from—it’s a “seat of the pants thing,” I suppose. Most networks today seem to run SPF in less than 10ms, though I’ve seen a few that Continue reading

Mac ransomware KeRanger has flaws that could let users recover files

The KeRanger file-encrypting ransomware program for Mac OS X contains crypto flaws that could allow users to recover their files without paying cybercriminals.According to researchers from antivirus firm Bitdefender, KeRanger is based on another ransomware program, called Linux.Encoder, that first appeared in November and targeted Linux-based Web servers.The first three versions of Linux.Encoder had flaws in their cryptographic implementations that allowed the Bitdefender researchers to create tools that could be used to decrypt files affected by the malicious program.To read this article in full or to leave a comment, please click here

Kernel Programming 101 – Creating your own Linux Kernel Module


Have you ever wanted to write your own kernel module? This multi-part blog post will talk about creating your first kernel module, using the proc file system, gathering and updating statistics and will cover topics such as your kernel as a menu items to menuconfig, setting defaults in the kernel config, registering network callbacks for specific types of packets taking Cisco CDP as an example and some tips-tricks in writing and debugging kernel code.  A lot of my own learning has been through blogs and experiments. One source that is really great and does summarize a lot of what my blog will talk about and more is TLDP (The Linux Documentation Project).

Today programming involving systems  is about providing the flexibility and pace for software development by providing user space APIs that interact with the linux kernel through system calls. This approach also provides the abstraction needed to carve out the complexity in direct kernel programming. So before we dive into kernel programming-101, lets answer this question - Why Kernel Programming? 

When there's need to perform operations without  cpu cycles wastage and/or reduce user space copy overheads, kernel programming suits the bill. Taking networking and linux networking stack as Continue reading

The Simple Leads to the Spectacular

 

Steve Kerr, head coach of the record setting Golden State Warriors (my local Bay Area NBA basketball team), has this to say about what the team needs to do to get back on track (paraphrased):

What we have to get back to is simple, simple, simple. That's good enough. The simple leads to the spectacular. You can't try the spectacular without doing the simple first. Make the simple pass. Our guys are trying to make the spectacular plays when we just have to make the easy ones. If we don't get that cleaned up we're in big trouble. 

If you play the software game, doesn't this resonate somewhere deep down in your git repository?

If you don't like basketball or despise sports metaphors this is a good place to stop reading. The idea that "The simple leads to the spectacular" is probably the best TLDR of Keep it Simple Stupid I've ever heard.

Software development is fundamentally a team sport. It usually takes a while for this lesson to pound itself into the typical lone wolf developer brain. After experiencing a stack of failed projects I know it took an embarrassingly long time for me to Continue reading

Worth Reading: Carrier Supporting Carrier

There is another technology called Carrier Supporting Carrier or Carrier of Carriers. This technology is used when a customer buys a circuit from an SP, Internet service or L3 VPN and that SP uses another SP to carry their traffic between the locations. The SP connecting the customer is then the customer carrier and the SP providing the backbone is the backbone carrier. -via Lost In Transit

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Microsoft to court: Make Comcast give us the Windows-pirating subscriber’s info

In the legal arena, Microsoft is going after Comcast in order to unmask the person behind an infringing IP address which activated thousands of Microsoft product keys stolen from Microsoft’s supply chain.The Redmond giant wants the court to issue a subpoena which will force Comcast to hand over the pirating subscriber’s info. If the infringing IP address belongs to another ISP which obtained it via Comcast, then Microsoft wants that ISP’s info and the right to subpoena it as well.From 2012 to 2015, Microsoft maintains that an IP addy assigned to Comcast pinged its servers in Washington over 2,000 times during the software activation process. “Detailed information” such as the activation key and IP address activating Microsoft products is transmitted to Microsoft; it’s considered to be “voluntarily provided by users.”To read this article in full or to leave a comment, please click here

Microsoft wants your phone to wirelessly log you into your Windows 10 PC

The slow death of the password continues. Microsoft's following in the footsteps of Google’s Chrome OS with a handy-dandy new Windows 10 feature that eliminates the need to manually log in to your PC.The company's currently testing a refreshed Authenticator app for Windows 10 mobile called Phone Sign-in Beta. It looks like the app will continue to generate codes for multi-factor authentication, but the star feature of the upgraded app is a new feature that unlocks your PC with one tap when your phone is nearby, as The Verge first reported.To read this article in full or to leave a comment, please click here

Juniper, Lenovo converge for next gen data centers

Juniper Networks has allied with Chinese IT stalwart Lenovo to build converged, hyperconverged, and hyperscale data center infrastructure products for the enterprise and webscale markets.The non-exclusive arrangement comes as the hyperconvergence market – tight integration of compute, networking and storage into an overall software-defined IT fabric – is reaching warp speed. Cisco entered the market last week via an alliance with start-up Springpath; HPE disclosed plans for an offering this month; and leading start-ups Nutanix and SimpliVity are expanding their product lines, ecosystems and addressable markets.To read this article in full or to leave a comment, please click here

Riverbed delivers the hyper-converged edge

Hyper-converged infrastructure in the data center has been all the rage over the past few years. In the data center, hyper-convergence is a system with tightly integrated compute, storage, network and virtualization technology. Its main value proposition is to simplify the architecture of the data center and enables it to be controlled through software. Despite the strong value proposition of hyper-convergence, the technology has remained focused on the data center with little applicability to the branch. The irony of this is that branch offices are often the lifeblood of organizations and is where the majority of work is done. Despite the criticality of the branch, the technology deployed in these locations is often old, inefficient and performs poorly and can often put businesses at risk. WAN outages cause application outages, which directly costs the organization money.To read this article in full or to leave a comment, please click here

Riverbed delivers the hyper-converged edge

Hyper-converged infrastructure in the data center has been all the rage over the past few years. In the data center, hyper-convergence is a system with tightly integrated compute, storage, network and virtualization technology. Its main value proposition is to simplify the architecture of the data center and enables it to be controlled through software. Despite the strong value proposition of hyper-convergence, the technology has remained focused on the data center with little applicability to the branch. The irony of this is that branch offices are often the lifeblood of organizations and is where the majority of work is done. Despite the criticality of the branch, the technology deployed in these locations is often old, inefficient and performs poorly and can often put businesses at risk. WAN outages cause application outages, which directly costs the organization money.To read this article in full or to leave a comment, please click here

Alpha Testing the AlphaLeon HTTP Bot

ASERT was initially alerted about an emerging threat called AlphaLeon by Deep & Dark Web intelligence provider Flashpoint in August 2015. It caught and kept our interest because it sounded like it could be a new “banker” malware family. While it took some time to find samples of the malware in the wild, this post […]
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