Category Archives: Technical Notes

All about technical notes

Fedora Quick Tip: Resolving Permission Denied Issues in HTTP and FTP services with getsebool and setsebool

If you are running Fedora Linux as a server, one issue you frequently encounter is strange permission denied error message triggered when you are accessing one of the available network services run on the server. There are a lot of network services to mention, but HTTP and FTP are two good examples of such services. Assume you are trying to access FTP server on your Fedora box. You type the IP address of the server and then supply the username and password. Voila!!! You thought you would be immediately logged in. But instead of seeing the files in your home folder, you are shown an error message. The error message may vary, from something like “Login incorrect for user blah” displayed by Midnight Commander, “500 OOPS: cannot change directory: /home/blah” from Total Commander, to other error messages shown by different FTP client programs.

If you are 100% sure that you supply the correct user and password information, why couldn’t you get in? Let us assume that you have root access to the server so that you can remotely troubleshoot from the console. This post will give some guide on how you can solve this problem based on common configurations of a Fedora server.
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Fighting Against Spam Comments, an Endless War for Blog Owners

I have been experimenting with comment settings in this blog to observe how willing spammers leave undesirable footprints aka spam comments on the blogs. Someone might have said that spamming is as pervasive as the web itself and it grows as the web evolves and reaches more audience. Still, having a hindsight experience in analyzing spam comment trending and behavior will be beneficial for me and also other website owners and bloggers especially when they are considering a loose commenting policy on their website.

Interaction in social web sites

As the web evolves to be more social, we can also observe higher level of interactivity on the web. Not only quicker page load, better content presentation, and improved system interface is interactivity characterized with, it also includes a simplified way of interaction among the website or web application users. In a bigger picture, interactivity encompasses user-application interaction and user-user interaction. If we talk about user-user interaction, we may think about creating such a user friendly platform for them to interact and communicate. Specific to blogging, user-user interaction can take form as commenting on the posts and also other user’s comment.

Now, here the question comes. If we can provide our users a friendly interface for interaction even for first-timers, can we expect for more quality interaction? And my personal answer to this is it depends on how good we are in implementing the website growth strategy. The first thing on which attention should be put thoroughly is the content. “Content is the king” is an undisclosed truth that tops the strategies towards website growth. I have been analyzing the growth of this technology blog by comparing number of posts in a certain month with the incoming traffic (user visits) for the corresponding month. I found two cases where traffic was higher than the average. The first case is the month with quality post(s) that drew users’ attention regardless of the total number of posts in that month. For the second case, it is the month with more posts, regardless of the quality, compared to the average monthly number of posts.
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Useful Zend Framework Resources for Developers, Users, and Enthusiasts

As I heard that Zend Framework 2.0 is on the way to the public release, I became curious to know how the framework had been evolving during the recent releases. I started to fiddle with Zend Framework again but also realized that I should update my comprehension and knowledge about the framework. It has been a while since I wrote a complex ZF-based application for the last time. I feel it is necessary to collect more information about framework; manual, technical notes, tutorials, case studies, people, communities, and so forth so that I can upgrade my knowledge and get back on the track again. I found a good compilation by Robert Basic that actually covers almost all things in my list. Still, I consider that providing an alternative list is far from being counterproductive. Instead, the information redundancy can be good especially when the lists complement each other.

Below, I categorize useful resources one can use to learn about Zend Framework. If you have suggestions about other resources to add, feel free to drop a comment and I will add it into the list.
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Quick Tip: How to Install and Configure PHP in Fedora Linux

Previously, I have discussed about how to install MySQL on Fedora Linux. In this post, I would like to elaborate PHP installation on Fedora. Even though the installation is simple by nature, I would like to provide some notes to help you troubleshoot some post-installation problems that may occur.

As usual, I will provide the screenshots of the installation along with the commands invoked on the terminal. For the environment, some important settings are written below:
OS : Fedora 13 64-bit
Web server : Apache HTTP Server
PHP version : PHP 5.3.2
Constraints : yum is installed, commands invoked in root shell, Apache is already installed and running

Note: Apache is installed by default in Fedora. You only need to configure and verify that the server is running. How to configure Apache is explained in the online documentation. If you want the server to be public, i.e. accessible from other computers in the network, you should not firewall the HTTP port, which is usually port 80. Also, if you enable selinux, you also need to properly set the flag of some security parameters related to http. I will explain about selinux and http in another post.

Now, let’s move to the installation. Basic installation steps are as follows:
1. Install PHP via yum

root# yum install php

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Quick Tip: Installing MySQL on Fedora Linux

Installing MySQL on Fedora has never been easier than before. If you are a first timer who wants to know how to install MySQL on a Fedora server or desktop, follow this guide to successfully install both MySQL client and server only in three steps.

Before you proceed to the installation, the environment settings for the snapshot pictures of the installation are provided below:
OS: Fedora 13 64-bit
Prerequisites: yum is installed, commands invoked on root shell
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