Comcast did WHAT in Houston? You are now a public hotspot.

Yesterday, Comcast flicked the switch that turns the home routers for 50,000 of their Houston subscribers into public Wi-Fi hotspots. It’s been covered in a few newspaper articles, I came across it on this SeatlePI article and this followup by Dwight Silverman.  Dwight writes for the Houston Chronicle, but I saw the syndicated copy on the SeattePI site.

If you live in Houston and have a XFinity Router, then you may already be a public Wi-Fi hotspot.  The router serves up the public Wi-Fi access on a separate wireless network from your home network.  But it’s using your bandwidth and the possibly the same IP address.

If you do a search of Wi-Fi networks and you see one or more named “xfinitywifi”, then your or your neighbor is now a public hotspot.  This is an opt-out policy.  Unless you request not to be a public hotspot, Comcast is going to enable it on your router.  Comcast had sent out letters to their customers, but how many of them read those letters?

The idea sounds good on the surface.  If you are a Comcast customer, you will have Wi-Fi access whenever you are close to another Comcast customer.  You would be able to connect your tablet or laptop in more places.

One problem with this is that you are sharing the bandwidth available to that home subscriber.  Comcast is making more bandwidth available to the home, but they can’t create more Wi-Fi bandwidth.  You can only carry so much network traffic over Wi-Fi.  If you live in busy neighborhood or close to a shopping area, other Comcast customers connected to your router could use enough bandwidth to make it difficult for you to connect to your own router.  Comcast can alleviate that with Quality Of Service (QOS) rules in the router, but that wouldn’t eliminate the problem.

Then you have the security issues.  Unless Comcast has modified the routers to get two outside IP addresses, anyone who connects to the public hotspot from your router will provide the same IP address to the rest of the world that you provide  This is the external IP address that shows up when you are connected to a website, not the internal IP address that your device thinks it has.    That means if someone was using BitTorrent to download and share copyrighted material like music or movies, it would be your IP address that would be tracked.

When Comcast gets the subpoena from the MPAA asking for the identity of the person using your IP address because that IP was sharing copies of “Frozen”, will Comcast be able to determine that the offending activity was done over the public hotspot as opposed to your internal network?  If they have the same IP address, then you are going to be facing the legal battle to prove your innocence.

If the public Wi-fi can be traced separated from your use of the same router, then Comcast has just made it easy for people to run Bittorrent sharing sites or perform other nefarious activity anonymously.  Just connect a Hotspot named “xfinitywifi”.  It can from your router or your neighbor’s.  It doesn’t matter, it’s not traceable back to you.  Comcast can block ports used by Bittorrent clients, but it will be hard for them to block everything.

You can opt out after the fact.  SeattlePI’s Dwight Silverman posted the following instructions here.

  • Log into your Comcast account page at
  •  Click on Users & Preferences.  
  • Look for a heading on the page for “Service Address.” Below your address, click the link that reads “Manage Xfinity WiFi.”  
  • Click the button for “Disable Xfinity Wifi Home Hotspot.”  
  • Click Save.

With the Comcast/Time Warner Cable merger currently in FCC review, this could affect more than Comcast customers,  If you are a Time Warner Cable customer, it’s possible that after the merger that public Wi-Fi program could be rolled out to TWC customers.  This is just one of those ideas that sounds good on people, but make me uneasy when they are actually implemented.

Been reading “iOS Development with Xamarin Cookbook”

iOS Development with Xamarin Cookbook

iOS Development with Xamarin Cookbook

A new Xamarin iOS book has just come out and if you’re programming for the iPhone on the Xamarin platform you will want it on your bookshelf.  It’s titled “iOS Development with Xamarin Cookbook” and is written by Xamarin MVP Dimitris Tavlikos.

This book will take you from the first steps in writing and compiling an iOS application with Xamarin to working with advanced topics like writing multi-touch gestures and working with iCloud.  The intended audience for this book are .NET developers new to iOS development and Objective-C developers who want to be able to use the Xamarin tools.

This is not a cross-platform guide.  While a few topics have corresponding features with Xamarin.Android, this is an iOS only book.  For example, chapter 12, “Multitasking”, covers the iOS specific APIs for running code in the background and how to respond to events raised by the background code.

The advantage of writing a guide for one platform is that Dimitris can go deep on specific features and APIs.  Each chapter has a set of “recipes” that explain how to do a task.  Each recipe is independent from the others.  You don’t have to build the first four recipes in a chapter in order to try out the code for the fifth.

Each recipe follows a pattern.

  1. Recipe Name: First Dimitris describes what the recipe will do
  2. Getting Ready:  What has to be done before the recipe code is written.
  3. How to do it:  A series of steps that describe the code to write
  4. How it works: An in-depth description of what that code does
  5. There’s more: Addition information about this feature
  6. See Also: A list of other recipes that are related to this one

For me, the book was worth it just for chapter 14, Deploying.  I don’t have to submit apps to App Store that often, it’s useful to have all of the steps required, all in one spot.