Using SSH Multiplexing

In this post, I’m going to discuss how to configure and use SSH multiplexing. This is yet another aspect of Secure Shell (SSH), the “Swiss Army knife” for administering and managing Linux (and other UNIX-like) workloads.

Generally speaking, multiplexing is the ability to carry multiple signals over a single connection (see this Wikipedia article for a more in-depth discussion). Similarly, SSH multiplexing is the ability to carry multiple SSH sessions over a single TCP connection. This Wikibook article goes into more detail on SSH multiplexing; in particular, I would call your attention to the table under the “Advantages of Multiplexing” to better understand the idea of multiple SSH sessions with a single TCP connection.

One of the primary advantages of using SSH multiplexing is that it speeds up certain operations that rely on or occur over SSH. For example, let’s say that you’re using SSH to regularly execute a command on a remote host. Without multiplexing, every time that command is executed your SSH client must establish a new TCP connection and a new SSH session with the remote host. With multiplexing, you can configure SSH to establish a single TCP connection that is kept alive for a specific period Continue reading

Technology Short Take #57

Welcome to Technology Short Take #57. I hope you find something useful here!

Networking

Block yourself from being tracked and profiled online  

This column is available in a weekly newsletter called IT Best Practices.  Click here to subscribe.  I don't often write about technology products aimed at the home user, but this is one I definitely want for my home. Small offices might find this product useful as well, and there is an enterprise version in development, so it's worth me telling you about what's on my wish list this time of year.I'm talking about eBlocker, a small device that protects your personal privacy when you are surfing the web. It's from a German engineering company of the same name, eBlocker.To read this article in full or to leave a comment, please click here

Google’s new Data Loss Prevention tools could drive enterprise adoption of Gmail

Enterprises that do not have an extremely large IT operating scale or unique compliance requirements don't have much of a reason to operate internal email systems. Yesterday, Google announced Data Loss Prevention (DLP) for its enterprise Gmail service, eliminating one more compliance reason justifying the operation of custom email services within the enterprise. DLP checks email messages and attachments for sensitive data to prevent disclosure to unauthorized personnel. Sensitive data includes trade secrets or intellectual property or data regulated in industries like healthcare and financial services.Innovation often takes a back seat to compliance; the more regulated the business, the more compliance becomes a roadblock to innovation. Before Google released DLP, the burden of data loss compliance standards prevented some enterprises from taking advantage of Gmail's 900 million mailbox scale. Few enterprises can operate email services with the redundancy, resilience, and security of Google's Gmail. DLP means that many enterprises running less-efficient email services for compliance reasons now have a Gmail option.To read this article in full or to leave a comment, please click here

If only this abandoned AT&T microwave tower could talk …

Oh, the stories it might tell. But since even the tower’s days of facilitating talk are behind it, a writer for The Atlantic has taken up the task of telling its story … or at least piecing one together as best as possible. From that account, which has better pictures: We were somewhere in Kansas when we found the second microwave tower. We’d found the ruins of one somewhere else in Kansas earlier during that day. This other one still had its pyramidal horn-reflector antennae intact. One abandoned microwave tower is a coincidence; two is probably an omen. Especially when that second one has AT&T Long Lines signage out front.To read this article in full or to leave a comment, please click here

Worth Reading: The Marriage of the Ecosystem

New technology is like dating. You get excited and giddy about where things are going and all the potential you see. You enjoy spending time together just talking or existing. As you start to get more serious you start to see issues crop up the need to be solved. Eventually you take the plunge and make things super serious. What you don’t want to have happen at this point is the trap that some people fall into. via networking nerd

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FBI director renews push for back doors, urging vendors to change business models

The FBI still wants backdoors into encrypted communications, it just doesn’t want to call them backdoors and it doesn’t want to dictate what they should look like.FBI Director James Comey told the Senate Judiciary Committee that he’d been in talks with unspecified tech leaders about his need to crack encrypted communications in order to track down terrorists and that these leaders understood the need.In order to comply, tech companies need to change their business model – by selling only communications gear that enables law enforcement to access communications in unencrypted form, he says, rather than products that only the parties participating in the communication can decrypt.To read this article in full or to leave a comment, please click here

When APIs and DevOps Meet Cybersecurity

Cybersecurity professionals often complain about the number of disparate tools they’ve deployed on their networks.  Ask any enterprise CISOs and he or she will come up with a list of around 60 to 80 various security tools from a myriad of distinct vendors.This has become a nagging problem as an enterprise cybersecurity architecture based upon point tools can’t scale and requires way too much operational overhead to maintain.  Thus, CISOs are moving in another direction – a tightly-coupled cybersecurity technology architecture based upon software integration.I’ve been following this transition for years and always thought it would look something like the departmental application to ERP migration of the 1990s.  Oracle, SAP, and lots of professional services built an interoperable software infrastructure connecting applications across the enterprise and soon dominated the market.  This is happening in cybersecurity to some extent as ecosystems form around the biggest vendors like Blue Coat, Cisco, IBM, Intel Security, Raytheon, Splunk, Symantec, and Trend Micro. To read this article in full or to leave a comment, please click here

SHA-1 cutoff could block millions of users from encrypted websites

Millions of Web users could be left unable to access websites over the HTTPS protocol if those websites only use digital certificates signed with the SHA-2 hashing algorithm.The warning comes from Facebook and CloudFlare as browser makers are considering an accelerated retirement of the older and increasingly vulnerable SHA-1 function.The two companies have put mechanisms in place to serve SHA-1 certificates from their websites to old browsers and operating systems that don't support SHA-2, but are still widely used in some regions of the world.These include Windows versions older than Windows XP with Service Pack 3, Android versions older than 2.3 (Gingerbread) and any applications that rely on OpenSSL 0.9.8 for encrypted communications.To read this article in full or to leave a comment, please click here

HTTP/2 For Web Developers

HTTP/2 changes the way web developers optimize their websites. In HTTP/1.1, it’s become common practice to eek out an extra 5% of page load speed by hacking away at your TCP connections and HTTP requests with techniques like spriting, inlining, domain sharding, and concatenation.

Life’s a little bit easier in HTTP/2. It gives the typical website a 30% performance gain without a complicated build and deploy process. In this article, we’ll discuss the new best practices for website optimization in HTTP/2.

Web Optimization in HTTP/1.1

Most of the website optimization techniques in HTTP/1.1 revolved around minimizing the number of HTTP requests to an origin server. A browser can only open a limited number of simultaneous TCP connections to an origin, and downloading assets over each of those connections is a serial process: the response for one asset has to be returned before the next one can be sent. This is called head-of-line blocking.

As a result, web developers began squeezing as many assets as they could into a single connection and finding other ways to trick browsers into avoiding head-of-line blocking. In HTTP/2, some of these practices can actually hurt page load times.

The New Web Optimization Continue reading

The Grumpy Old Network Architects and Facebook

Nuno wrote an interesting comment to my Stretched Firewalls across L3 DCI blog post:

You're an old school, disciplined networking leader that architects networks based on rock-solid, time-tested designs. But it seems that the prevailing fashion in network design and availability go against your traditional design principles: inter-site firewall clustering, inter-site vMotion, DCI, etc.

Not so fast, my young padawan.

Let’s define prevailing fashion first. You might define it as Kool-Aid id peddled by snake oil salesmen or cool network designs by people who know what they’re doing. If we stick with the first definition, you’re absolutely right.

Now let’s look at the second camp: how people who know what they’re doing build their network (Amazon VPC, Microsoft Azure or Bing, Google, Facebook, a number of other large-scale networks). You’ll find L3 down to ToR switch (or even virtual switch), and absolutely no inter-site vMotion or clustering – because they don’t want to bet their service, ads or likes on the whims of technology that was designed to emulate thick yellow cable.

Want to know how to design an application to work over a stable network? Watch my Designing Active-Active and Disaster Recovery Data Centers webinar.

This isn't the first Continue reading

A Few Easy Steps: Cisco Switch, Setup IP Device Tracking

In this session of A Few Easy Steps, we will be setting up IP Device Tracking on a Cisco IOS Switch. In General this will work on any Cisco IOS switch.  Session Prerequisites: You have terminal or console access to your Cisco device. Session Assumptions: You have host devices connected to your switch Our goals of …

Companies scramble to fix lack of encryption on mobile apps

Several companies have moved quickly to add encryption to their mobile apps after it was discovered they failied to encrypt payment card information in transit, putting users at risk. The apps were not using SSL/TLS (Secure Sockets Layer/Transport Layer Security), an encryption protocol that scrambles data as it's sent across the Internet, according to Wandera, a cloud and mobile security vendor. "With so many breaches and costly data loss incidents in the news, it's hard to believe that any business would fail to take such a basic precaution as to encrypt sensitive traffic as it's transmitted to or from a website," said Michael J. Covington, senior product manager, in a video posted Wednesday.To read this article in full or to leave a comment, please click here

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