2008

Business / Hardware / Software — View Comments
4
set 08

Mobile Hotspot – Wi-Fi in your car, bus, taxi cab, …

Today we launched our first pilot of the VexBox Mobile Hotspot solution. It’s our linux distribution with a new hardware that can take the internet from 3.5G, 3G, EDGE or GPRS, whatever is available and faster. It can be used in places where fiber doesn’t reach or buses, taxi cabs, cars, …

It’s been months doing reverse engineering to understand how the hardware works, also writing the device drivers for a chip that is not perfectly designed and well, we made it! October 1st is the official launch date.

Congratulations for all the team, I know you all worked very hard to make this come true!

They wrote good code, so let’s not complain about the pictures:

Business / Computer Science / Software — View Comments
4
set 08

What actually 802.11r do?

After 4 years of hard working, IEEE approved the standard 802.11r, which handles a fast BSS transition.

What this means?

A big wireless network, is built with a lot of access points, this means that if you would like to cover a big city, you might have thousands of access points spreaded around.

This brought a new challenge to 802.11, with the introduction of applications such as voip, the transition between access points needs a very small delay, you would be amazing how annoying is to have a delay bigger then 300ms, can turn your call into something unacceptable if you are roaming into access points too fast.

Of course if you are walking in this city, it will not interfere much because you are slow, but if you are inside a car, you might be changing access points every five seconds, and this is where you’ll find the big problem. We already had the possibility to roam through access points at 100ms (802.11F), but this standard was defunct in 2006 giving space for r, which can roam twice as fast, 50ms, standard for voice transition.

What it basically do is allowing your software client to stabilish a new access point connection before actually switching for it, with this you can do the magic of roaming almost atomic in whatever state the access point is.

Business — View Comments
28
ago 08

How to NOT apply for a job

Two days ago I posted a job opportunity in one of those sites where engineers and computer professionals watch often, I described the company and the profile I was looking for very carefully, in the end of the profile I made one simple request:

Include your salary expectation

I did it in the late evening and early in the morning it was already appearing in the website and I already received a bunch of applications. Checking one by one, I noted that most of the applications didn’t do the simple request, like usual.

How experienced people don’t realize this can show so much about them:

  1. You have no attention
  2. You ignored a simple request

Some times I think people don’t care about quality, they just want to send as much resumes as possible. For me and most of the companies is very simple, click delete.

Business / Software — View Comments
26
ago 08

Hacking commercial wireless

Lately a number of blogs posted comments on a very old post, dated 2006 about how to hack a commercial wireless, goes like this:

“I continued to try a couple other things, like checking if they eventually forgot some ports like 21 (ftp) or 110 (pop3). But no, all of them were properly blocked. After a lot of unsuccesfull attempts, I had some intuition telling me to check how they handle pictures. Without any hope of success I typed http://www.google.com/.jpg into my browser’s adress bar, and to my big surprise I saw the page you see when you follow the link right now. The next thing I typed in was: http://www.google.com/?.jpg but that didn’t work. But I went on, and found that url’s like http://www.google.com/search?.jpg worked like a charm. I found that I could easily visit sites like slashdot, google, or even this weblog, when adding a ?.jpg at the end of the url. The next logical step was to automate that. I downloaded greasemonkey.xpi?.jpg (*g*) and wrote a 4 line js script that would add ?.jpg to every link in a document. That way I was able to browse most sites without a hassle. Unfortunatly, I didn’t get to explore this vulnerbility much more, because I had to board the airplane, were I waited another 3 hours due to a mechanical failure – without wlan : /.”

What normally happens in a router with captive portal is, you have a firewall rule that redirects you to a local http server, this server gets a bunch of information about you, like ip address, mac address, url you tried to access and so on, then it displays a website so you can log in.

If this local web server or called application that redirects you is bugged, might help you get free access, but I really doubt this will work on any network, but I can’t talk about others, in Vex, this by far will not work.

Business / Software — View Comments
25
ago 08

Canada blocks outgoing email

Few weeks ago I was in Vancouver for a few meetings, while in this company that produces routers, they told me that they also offer a mail service that can come within the router, making absolute non-sense for me, I asked:

Q: “why?”

A: “Most ISPs in Canada blocks port 25″

*sigh*

Q: “Why?”

A: “They think this way they will block spam”

*sigh*

It’s incredible how from time to time you can hear incredible ideas like this, how come no one ever realized that blocking port 25 would reduce spam, uh? Because of this fantastic solution this company has to provide an alternative way for their clients email to be delivered successfully, then I ask you:

How complicated is for a spammer to do the same?