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Free software licenses, definitions, types and compatibility

Posted by Pablo Gonzalez on January 8 2013th

In this article we will continue with free software licenses, definitions, types and compatibility.

Therefore, we will initially treat several definitions and subsequent years of introduction:

- Freeware: These are free programs that are usually distributed compiled. If we want to redistribute such software usually must ask the author permission. This type of software is used for propaganda in other software with more features and usually pay.

- Shareware: It is a method where the program distribution may be limited in function of a time period. Payment is usually done because these programs have propaganda, limited functions, etc ...

- Public Domain: The author waives his rights and give them to mankind. By default, a program that does not specify anything in the public domain, therefore, must be expressly stated in the software.

- Permissive licenses: Non-copyleft license that allows distributing the software under another license. Could even distributed under a proprietary license. Example, BSD.

- Licenses robust (copyleft): The license requires that the modifications are distributed free. Example, GPL.

It is important to examine and verify the licenses are not mutually incompatible. For example, a program that blends a license GPLv3 GPLv2 with inconsistent because GPLv3 violate Article 6 of GPLv2 as this does not allow adding more restrictions. If we use the GPLv3 add the restriction to provide information on facilities. From this it generates a mismatch.

Keep in mind that we want to license our software, as it will be compatible or not with other changes becoming more difficult in the future.

As a personal opinion, nowadays, prefer permissive licenses that allow even a modification under a proprietary license. This I consider a paradox, since the warrant permissive freedoms of all (even those who want to make it exclusive), but on the other band, each eliminates proprietary license and freedoms goes against keeping them.

Nevertheless, I think it is best that everyone can choose what they want to do with their freedom.

NOTE: The Linux project is generated GPLv2 licensed. The use of DRM systems can implement GPLv3 * restricting modifications to the program code not authorized by the hardware. What will happen to our open source software is not signed by the hardware? Decide yourself ...

* They are mechanisms or rights management technology to protect digital copyrights.

Now remember the freedoms 4:

a) The freedom to run the program for any purpose.

b) freedom to study the program, modify it as needed. We need access to the source code.

c) freedom to distribute copies of the program.

d) freedom to improve the program and launch it. We need access to the source code.


- The type of software Freeware grants users access to the source code and allows modification and study. True or false?

- The free software licenses allowed to be redistributed as proprietary software? True or false?

- Imagine a program with modified GPL license, do requires us to distribute the modified source code?

- Why is the original BSD license 4 clauses incompatible with the BSD GPLv2 but 3 clauses if it is compatible?

In the following article we will see some more examples of dual licensing software, discuss project management models and some exercises and examples.

I hope you find it useful.

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Mail server installation EXIM4

Posted by Pablo Gonzalez on July 3 2012rd

Good afternoon, in this article we will see how to makeMail server installation EXIM4with a dynamic IP address.

Personally, I do not recommend this configuration because we have serious problems blocking blacklist, so, this article has only academic value. To inspire the reader to other servers and services.

We start from an installation of GNU / Debian default 6 in an old notebook.

Add repositories / Etc / apt / sources.list

deb squeeze main contrib non-free
deb-src squeeze main contrib non-free

rename with # the line that begins with deb cdrom.

We enter the following command with the username root:

aptitude update (With this update we have added the repositories above).

Install the no-ip client, since I have dynamic ip address and in many cases (the vast majority) must match the domain to your ip when mail is delivered, otherwise, the target server will consider it as spam. I assume that you generate a suitable account if necessary.

We can decompress with xvzf tar noip-duc-linux.tar.gz and we will create a folder.

We continue with the following commands:

cd-2.1.9-1 noip

make install noip2.c

We requested email address, password and the update interval, which in my case I have considered going down to 5. We also ask if you want to run any programs in each update, and in my case I select No.

We generated the configuration file non-ip2.conf. Megacrack read »

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Posted by Mail, GNU / Linux, Linux | No Comments »

Early free software II

Posted by Pablo Gonzalez on June 9th 2012

"If you have an apple and I have another apple and we exchange the two continue to have an apple, but if you have an idea and I have another idea we'll both have two ideas."

Bernard Shaw

This is one of my favorite lines, but in the times in which we are, where the licenses and rights are the order of the day and we played a lawsuit, this is not so easy.

For this reason, in this article we will deal especially basic legal issues in subsequent articles and talk of free licenses.


Intellectual property:

We can identify the intellectual property copyright (copyright) that protect the works from unauthorized copying.

Intellectual property is protected and coordinated by the World Intellectual Property Organization (WIPO) by the agreements which are forced in the participating countries of the World Trade Organization to comply.

The Universal Declaration of Human Rights recognizes in its articles the right to moral and material rights of their works are protected, so that his philosophy is to try the authors of the idea "reward". Remarkably, when the promotion ends or validity, intellectual property expires.

The mission is that through intellectual property can provide a competitive advantage to the author of the idea to exploit during the term of intellectual property.



Initially it was created to protect rights to authors of art and books.

This protection helps protect ideas, expressions and knowledge. What you need to be very, very clear it is that these rights are immediately begin to publish the work, but not put (c) in our work.

Example, I make a picture and the public without indicating that the public domain or any other license, this photograph has a copyrigh, copyright preventing any use without notice and in case of breaching it can proceed with a lawsuit.

If you want to protect a copyrighted work recommend going to the notary and protect it. In this way we can show later copies.

Formalized by the Berne Convention in 1886.


Patents and trademarks:

At this point I will be very brief, patents and trademarks are registered because normally represents quality and value in a market.

The curiosity here is that this type of law is provided from the 15 25 the years.

View this site it is very interesting to search for patents and trademarks in Europe and USA we can use the page

As an example, I searched the trademark "LinEx" distribution created in Extremadura for a very interesting project discussed below, and I found:


  • Case file:M 2449568
  • Distinctive Type:D
  • Date of situation:16 / 11 / 2002
  • Nice Classification:09

Hence, we can extract much information, but something that is not so obvious is the "Nice Classification" which is a standard that informs us of the classification of this brand. To view this classification see the following page:


Trade secret:

Based on the advantage in that the company protects their works through industrial property.

A typical example may be the evil empire, where their proprietary programs compiled and provided to us to reverse engineer is considered a crime.


Let's look at the license for example Windows XP, paragraph 4:


DISASSEMBLY. You may not reverse engineer, decompile, or

disassemble the Software, except and only to the extent that such activity is expressly

permitted by applicable law notwithstanding this limitation.


In the next issue we start with the free licenses, definitions, types and compatibility.


I hope you find it useful.

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Posted by GNU / Linux, gnu / linux, Linux | No Comments »

Early free software I

Posted by Pablo Gonzalez on June 8th 2012

We begin this part of the blog as it should, from the start :-).

First a little history ...

In 1991 the Finnish student Linus Torvalds announced on the Internet for developing a core operating system and donated it to the community to function properly checkear.

This kernel Linux became ...

The foundation "Free Software Foundation (FSF)" from 1984 free software generated with GNU. Thanks to the vision of Richard Stallman who was a member of the FSF and promoted the software as a free tool where business models were: maintenance, training, additional services, literature searches, etc ... it started developing a series of free applications and quality.

At the junction of these two projects was born the environment we now know as GNU / Linux.

For this reason, we can not call it "Linux" is wrong, and his real name is GNU / Linux!.

To not ramble too much, just wanted to clarify that this combination was achieved by moving from concept to Open Source Free Software (Open Source) and this was recorded and produced a small conflict between the FSF and Open Source. Do not go into more detail here.

In 1997 Bruce Perens Open Source definitions generated later the Open Source Initiative (OSI) re-edited and published.

Importantly, and remember the following items that the OSI will be responsible for managing open source licenses. For more details see: and licenses approved by OSI,

(On the licenses discussed in another chapter, as it is interesting to spend time and inclination!).

I leave a link that shows when Linus Tovards community makes this great milestone and what we know today as a great operating system:

Megacrack read »

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Posted by GNU / Linux | No Comments »

Training program on free software (Introduction)

Posted by Pablo Gonzalez on June 8th 2012

Some time ago, my colleague told me xavixaus help in the development of the environment Free softwarefor this blog.

Well, it's already time to start it, and first I would like to comment briefly on how we will organize it.

First we will make an introduction to this world and see some aspects legalwe need to know, whether we are users and programmers, case studies to try to put the different concepts and continue to appreciate Basic management environments GNU / Linux(Choice of our distribution, installation, basic commands and routing).

The second part of this chapter will be the advanced administration in which address issues such as installation and compilation of the kernel and modules, NIS servers, exim4, LDAP, WebDav and Apache, authentication, snort, MySQL, subversion ... and something more ...

In the next module we will give some management, A staple for a migration to free software environment, with guidelines and best practice guidelines. At this point we will refer to success stories in government.

I think it's also interesting to do a course on free software utilities such as DIA, LibreOffice, forges where to find substitutes to proprietary software, etc ...

Finally, I would like to end articles with networks, focusing on routers, security (basic), audio, video and IP telephony.

It is an ambitious plan for each chapter because many items will be generated and we would like to implement a test environment to display settings and "tweak" the system. This last point for now is an idea. We will gradually giving.

I hope you enjoy it and bear your opinions through comments.

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Posted by GNU / Linux, gnu / linux, LDAP, Linux | 1 Comment »