How to hide (obfuscate) any traffic using obfs4

Overview

In this post, I’m going to give you the information necessary to be able to use obfs4 protocol not just for wrapping Tor traffic, but for virtually any other TCP traffic as well.

Doing so for the previous Pluggable Transports of this kind (namely obfs2,obfs3 and ScrambleSuit) was rather simple. obfsproxy program written python, already supports being run in standalone (or so called unmanaged) mode and there are dozens of guides available on how to do so.

However, obfs4proxy which implements obfs4 protocol in Go, is primarily designed to work in conjunction with Tor (managed mode). This is not a protocol limitation but rather an implementation one.

If you ever try running obfs4proxy by itself, you’d get an error like this:

[ERROR]: obfs4proxy – must be run as a managed transport

But Hey! It is not the end of the world. There are still couple of ways to make use of obfs4 outside of Tor:

  • Adding unmanaged mode of operation to obfs4proxy
    This is probably the best way, but I’m not a Go programmer so I’ll leave that to those who are.

  • Using external wrappers
    PTProxy and ptadapter in Python, along with Shapeshifter in Continue reading

IPv6 in China

China has an estimated Internet user population of 741 million, out of a total population of 1.4 billion people. If there was extensive deployment of IPv6 services in China, then the case that IPv6 has already achieved critical mass of deployment would be easy to make. On the other hand, if such a significant user population had no IPv6 service and no visible plans for IPv6 services, then the entire conversation about the times and certainties about the future of IPv6 takes on a different direction. Which means that China matters in the world of IPv6. It matters a lot.

My Ignorance for a Year and Dell IDRAC

Hi,

I have a Dell R810 and it makes a lot of noise. So, I have put it somewhere remote in the home where it’s completely inhabitable for human beings. Now, the problem was always to go there and manually power-up the system.  This has been the scenario for years. So, technically if am away from my home I need to take help from my wife. All this is going well and I was always wondered should it not have a better way to do things.

Was talking to my friend and he had some paid solution for the same thing, he doesn’t even remember and that’s for his cisco gear, now for Cisco gear as long you supply power they will be powered (if the Power button is always on), for servers however just like our Personal CPU’s and Laptops you have to manually press the power button.

Then yesterday all of a sudden I took this somewhat seriously and explored options, then I understood it was sitting right inside the server, Dell has something called Integrated DRAC system which helps you do this thing, all you need to have is a proper Lan connection, the message was Continue reading

Testing notes: simulating link failure by filtering BFD packets

In some testing I am doing, I need to prove that BFD can be used with iBGP to tell the BGP protocol when there is an interruption.  This will enable BGP to be brought down much faster than if regular BGP timers are used.

To make this easier to do, I used a firewall filter on one of the two routers to filter out BFD but accept all other packets:
Single-hop BFD (i.e. across a link) uses UDP 3784, while multi-hop BFD uses 4784.  Since my BFD sessions are configured between loopbacks, it is this latter type I need to filter.

In the example below, CORE1 is a BGP client of CORE2, which is the route-reflector.

The following was configured on the routers to bring up the BFD session (I am only showing one side – you can figure out the mirror of this yourself I think):

[edit protocols bgp group CORE neighbor 10.0.0.6]
      bfd-liveness-detection {
          minimum-receive-interval 300;
          multiplier 3;
          transmit-interval {
              minimum-interval 100;
          }
      }

When the remote side was done, the session came up:


axians@CORE1> show bfd session
Dec 28 17:17:10
                               Detect Transmit
Address       State Interface  Time   Interval  Multiplier
10.0. Continue reading

Top 5 Blog Post 2018: Simplifying Kubernetes with Docker Compose and Friends

All this week we’ve been bringing you the top 5 blog posts for 2018 –coming in at #1 is our post on open sourcing our Docker Compose on Kubernetes capability. This new capability enables you to simplify the Kubernetes experience. To learn more, continue reading…     

Today we’re happy to announce we’re open sourcing our support for using Docker Compose on Kubernetes. We’ve had this capability in Docker Enterprise for a little while but as of today you will be able to use this on any Kubernetes cluster you choose.

Compose on Kubernetes

Why do I need Compose if I already have Kubernetes?

The Kubernetes API is really quite large. There are more than 50 first-class objects in the latest release, from Pods and Deployments to ValidatingWebhookConfiguration and ResourceQuota. This can lead to a verbosity in configuration, which then needs to be managed by you, the developer. Let’s look at a concrete example of that.

The Sock Shop is the canonical example of a microservices application. It consists of multiple services using different technologies and backends, all packaged up as Docker images. It also provides example configurations using different tools, including both Compose and raw Kubernetes configuration. Let’s have a look Continue reading

LibreRouter: A Multi-Radio Wireless Router for Community Networks

Since their inception, community networks have depended on modifying existing off-the-shelf routers to adapt them to their particular needs. Software development originated in community-network groups and the free software movement as a whole have pushed the barrier of innovation and helped commercial enterprises develop new products over the years.

The LibreRouter, created by the collaboration of the Internet Society Community Networks Special Interest Group (CNSIG) and AlterMundi with the support of Beyond the Net Funding Programme, is an open-source hardware WiFi router designed for the specific needs of community networks.

The LibreRouter Project works to achieve autonomy and technological sovereignty that allows deploying, managing, scaling, and sustaining community networks. The reality is that community networks are not a profitable market segment for the industry. This means that the equipment used is not adequate to solve the particular needs they have. To manufacture the equipment you have to be encouraged to understand it and do it in a different and integral way.

Besides the hardware development, the most important part of this project is the integral work that involves software solutions and documentation material. It’s an important work focused on the communities themselves having the capabilities to deploy their Continue reading

SD-WAN – Glorified DMVPN?

I had an interesting discussion with Jon Cooper in the Network Collective Slack. The discussion was around SD-WAN. We were discussing if SD-WAN is just a “glorified DMVPN” or if it’s something more than that. Note that this was a bit tongue in cheek comment from Jon but it’s interesting for the sake of discussion.

To compare the two, let’s look at some of the design and operational challenges of running a DMVPN.

Physical design – How many Hub routers do you need? In a DMVPN, the Hub router is a special type of device that is responsible for mapping the underlay IP address to the overlay IP address. If a Hub needs to be added, this Next Hop Server (NHS) needs to be added to the spokes. With Cisco SD-WAN, this is handled by the vBond which is a virtual machine running in a public cloud. Adding a device is simple as the WAN edge routers use a hostname (DNS) to ask for the IP of the vBond. This means that the physical design is less rigid.

Logical design – In a DMVPN, you need to decide on the number of DMVPN clouds. Do you do a single cloud Continue reading

The Year in Review: Governments Try to Restrict Free Speech Online and Break Encryption

In 2018, the Internet saw concerted government efforts to restrict free speech on the Internet – some in the name of fighting “fake news” – and to compromise encryption on devices and messaging apps.

Can the government decide what’s fake news? Several countries either passed or explored laws intended to combat so-called fake news and online disinformation. In some cases, the laws contained significant prison time for those who create or disseminate fake news.

The problem, of course, is that the government decides what’s fake and what’s legitimate news. Free speech advocates have warned that the anti-fake news laws amount to censorship, with government officials playing content gatekeepers.

In Malaysia, the fake news law was quickly used to investigate an opponent of the administration in power. Malaysia repealed its anti-fake news law about four months after it passed, when opposition leader Mahathir Mohamad, one of the first people invested under the law, became prime minister.

In November, France passed its own anti-fake news law, allowing judges to determine fake news and order its removal. Distributors of news determined to be fake can face one year of prison time. India also considered but abandoned a fake news law earlier this Continue reading

Improving request debugging in Cloudflare Workers

Improving request debugging in Cloudflare Workers

At Cloudflare, we are constantly looking into ways to improve development experience for Workers and make it the most convenient platform for writing serverless code.

As some of you might have already noticed either from our public release notes, on cloudflareworkers.com or in your Cloudflare Workers dashboard, there recently was a small but important change in the look of the inspector.

But before we go into figuring out what it is, let's take a look at our standard example on cloudflareworkers.com:

Improving request debugging in Cloudflare Workers

The example worker code featured here acts as a transparent proxy, while printing requests / responses to the console.

Commonly, when debugging Workers, all you could see from the client-side devtools is the interaction between your browser and the Cloudflare Worker runtime. However, like in most other server-side runtimes, the interaction between your code and the actual origin has been hidden.

This is where console.log comes in. Although not the most convenient, printing random things out is a fairly popular debugging technique.

Unfortunately, its default output doesn't help much with debugging network interactions. If you try to expand either of request or response objects, all you can see is just a bunch of lazy accessors:

Improving request debugging in Cloudflare Workers

Continue reading

Will Cisco Viptela continue to be one of the Leaders in SD-WAN ?

In 2017, Cisco completed Viptela acquisition. It is not a surprise for me that Gartner published Cisco as the Leader in WAN Edge Infrastructure in 2018.     This is Gartner’s famous Magic Quadrant report.  I wrote a post for Silverpeak  before.  Silverpeak is listed in the Leaders category. Three vendors presented their solutions and I …

Continue reading "Will Cisco Viptela continue to be one of the Leaders in SD-WAN ?"

The post Will Cisco Viptela continue to be one of the Leaders in SD-WAN ? appeared first on Cisco Network Design and Architecture | CCDE Bootcamp | orhanergun.net.

Looking Back: 2018 Project Report Card

Over the last five years or so, I’ve shared with my readers an annual list of projects along with—at the year’s end—a “project report card” on how I fared against the projects I’d set for myself. (For example, here’s my project report card for 2017.) Following that same pattern, then, here is my project report card for 2018.

Here’s the list of projects I established for myself in 2018 (you can also read the associated blog post for more context):

  1. Become extremely fluent in Kubernetes. (Stretch goal: Pass the CKA exam.)
  2. Learn to code/develop in Go.
  3. Make three contributions to open source projects. (Stretch goal: Make five contributions.)
  4. Read and review three technical books. (Stretch goal: Read and review five technical books.)
  5. Complete a “wildcard” project.

So, how did I do? Let’s take a look.

  1. Become extremely fluent in Kubernetes: This is, in my opinion, a hard one to accurately gauge. Why? Well, Kubernetes is a pretty massive project. I saw a tweet recently saying the project was now at a point where no one person can understand all of it. The other factor making it difficult for me to accurately gauge this is the caliber Continue reading

DNS-over-TLS in Linux (systemd)

Whilst we were putting together some content about DNS privacy recently, we learned that recent distributions of Linux ship with support or this. We therefore decided to give Ubuntu 18.10 a try on a laptop.

More recent versions of Ubuntu employ a special service for name resolution called ‘system-resolved.service(8)’. The configuration file ‘resolved.conf(5)’ specifies most of the details for name resolution, including which protocols and resolvers should be employed, whilst the ‘/etc/systemd/network/*.network’ configuration files (see ‘systemd.network(5)’ for details) of the ‘systemd-networkd.service(8)’ specify any per-link specific settings.

The default configuration of ‘systemd-resolved’ is selected at compile time, and ‘/etc/systemd/resolved.conf’ normally contains commented-out lines describing such defaults. For example, the contents of the aforementioned file on a fresh Ubuntu 18.10 installation are:

As may be inferred from the file, DNS-over-TLS (DoT) is supported, but disabled by default. At the time of  writing, only opportunistic DoT is supported according to the manual, which means that the resolver will first try resolution using DoT before falling back to traditional DNS in the event of failure – thus allowing for downgrade attacks where an attacker intentionally causes a DoT failure in order to cause name resolution to downgrade Continue reading

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