Encryption ... rap?

Rapper MC Plus+ has created a song titled "Alice and Bob" based on the improbable theme of computer cryptography. It is freely available online. I'm not sure this will become a huge hit but, who knows?

New software threats

As I mention in the last class, I read this post where new types of malware activity are commented. While I am not afraid this will have a wide effect it is a new twist as to how some people can turn out a benefit from creating this particular type of sofware.

Last assignment is out

This last assignment is about finding the best route in a graph. This is part of what a routing algorithm does. Actually, a routing algorithm will search for all the best routes to all the destinations.

Moore's law of networking?

Apparently, there is a Metcalfe's law about the value of a network I have never heard before. All it all, it does not seem to make everybody happy. I guess Metcalfe will be better recalled because of Ethernet technology.

Getting to know an autonomous system

In this link you can learn more about this ISP's set of addresses. Comsat Colombia is the local branch of an international ISP that offers satellite Internet access. In the report all the BGP-related information is shown, so you can learn about their addressing space and the other AS they are routing through.

For those of you that feel happier with a closer ISP. Here you have the ONO-CableEuropa AS details.

Third assignment

As we are studying IP fragmentation, it seems appropriated to get some hands-on experience on the topic. This is what this third assignment is all about.

Please remember this is just an optional programming exercise dealing with computer network's concepts. But if you decide to go for it you'll get the double benefit of learning plus scoring a bit towards your final grade.

Back to work

Exams' period is over. We've got an interesting second term where we'll cover from IP network-layer to LANs and network security. For those of you new in the subject I want you to know that we'll have a couple programming assignments this term. For you all remember that attendance to the lectures while not mandatory is recorded and it will be marked (sometimes you can even learn something new).

See you in class next Feb, 16th.

Exam results

You may want to get a copy of the exam with all the answers too. It's already here.

               EXAM      LAB.TEST   ATTENDANCE  TOTAL
Jorge          63%         55%         1        70%
Luis Manuel    38%                     7        37%
Ignacio        73%         55%        27        87%
Alberto        41%                     6        39%
Diego          59%         40%        22        73%
Johan          57%         20%        19        65%
Tomasz         67%         80%        20        82%
Vladislav      63%        100%        22        82%

Solved lab test is also available.

The column "total" includes your assignments too (if any).

Marks are calculated as follows:

TOTAL = EXAM * (9 - #ASSIGN) / 10 + #ASSIGN * 10 + ATTENDANCE * 10 / 27 + LAB.TEST / 10

Fall term is over

Lectures are interrupted till the beginning of Spring term. I guess we'll keep you busy with exams. Please remember there is still one week to turn in assignment #2.

My best wishes with the exams.

Johan, we'll miss you.

Maybe some new students will join us next term.

Some help for Lab #5

I've just learned about this site. It contains interesting information about almost everything on the course. I'm not sure how good the book is but, never reject any extra help.

I recomend you to read and understand the goals of Lab #5 before going to the Lab. It might be more complicated that previous ones . You might need all session's time to complete the proposed exercises.

Assignment #2 is out

It can be obtained from here and it is due by January, 27th.

Please remember there are just a few days left to turn in assignment #1 (due by Dec, 13th).

Web-based nslookup

Easier than the nslookup command-line tool and independent of your operating system, this site gives you answers to any of your DNS records curiosity.

One example of securing POP3 with SSL

This example comes from Google's Gmail POP configuration.

Note the checked "Use secure connection (SSL)" on the left image (you will need to click on it to make it readable).

With it, any eavesdropper will see just random bytes instead of a nicely crafted ASCII dialog. So capturing username and password or the nature of the exchanged messages is now quite difficult.

Spanish Research Network Infrastructure

This one is the network UPV is connected to. As you can see (click on the image for a better view) Valencia is connected using several 2.5Gbps channels: Not bad!!

MIME and Transfer-Encoding

Common encoding schemes used by MIME include base64 and quoted-printable. Please note the goal here is to keep the text transmitted using SMTP protocol as 7-bit ASCII code regardless the original message contents. This transfer encoding will be undone on the receiving end to restore the original message. This way, images, sounds and any other binary contents can be sent as SMTP email.

Java Sockets Source Code

I've posted some of the Java source code we used in the classroom lately.

As we mentioned in the class, the conversion between bytes and characters depends on the encoding scheme. Most current Operating Systems no longer use ASCII but other schemes like UTF-8 to encode text-file contents. That is why we prefer the use of *Reader and *Writer classes instead of just the byte streams. (Why is encoding important?).

Java Sockets' Programming

Now you might want to download the JDK to your system so you can compile your own Java code. I know some of you have used other tools, like BlueJ, but the JDK is the real deal and the full class-library docs are here.

HTTP result codes

Detailed list of HTTP result codes. But if you need any more detail you can check the current up to date RFC-2616. Please note that Postscript or PDF versions of the document are available in the same page in case you do not feel comfortable with the ASCII-only version.

First assignment is out

You may want to wait some days before starting to work on it as some topics have yet to covered in the lectures. But your first assignment is available. I want you to remember these are optional exercises you may or may not do. But if you do the assignment right (right meaning that it works), then you get a 0.45 points per assignment to be added to your final mark. If you are in doubt of what that means I suggest you to check the assessment details presented on chapter 0 slides.

I do not want to repartition my PC hard drive

You've noticed by now that our lab exercises are mostly Linux-based. This is for a reason: All the software we use at the lab is freely available. But it is very likely you have a Windows-only PC. Fear no more, you may use Knoppix (fantastic Linux distribution that boots up from a CD or DVD). It contains all that you need to complete most of the exercises without installing anything on your PC, just boot the system off the CD media. You can download the latest version from this FTP. As it is an on-campus mirror you should expect ultra-fast download. Just burn the ISO and that's all. You'll find a complete desktop, development tools, Java-support, audio and video players, and some games too. And you can't beat the price. Feel free to share it.