Switches, Routers, Wires and speed As usual internet was fast on ubuntu as it used to be till I needed to plug more PCs into the adsl route lying nearby. After connecting all computers and the adsl router to a switch I noticed that on one of the PC (Ubuntu 8.04) internet became really slow…. Read More »
Install Postgresql , phpPGAdmin and pgadmin 3 can be installed from synaptic. $ sudo apt-get install postgresql phppgadmin pgadmin3 After installation some configuration needs to be done. First of all setup the password of the user ‘postgres’ which is the default user of postgresql. Type the following in the terminal $ sudo -u postgres psql… Read More »
Automatic Running In a web application there are many cases, when a certain piece of code or script needs to run automatically in the background to perform certain tasks, without the need of any user to start it. Like scraping, extracting or crawling data from web or perform some regular tasks like sending emails, system… Read More »
The PHP function set_time_limit is used to set a time limit on the maximum execution time of a script. But if the script has socket operations using fsockopen , fread and fwrite or even CURL then the set_time_limit may not appear to have any effect on the scripts timelimit or timeout. Again if safe mode… Read More »
Apache Mod Rewrite mod_rewrite is an apache module which enables rewriting of urls requested by client before the pages are fetched by apache. For example www.site.com/products.php?code=459 can be written as www.site.com/products/459 or www.site.com/products/459.html. The second url is re-written into the first one by mod_rewrite using rewrite rules specified in the .htaccess file. Enable Mod Rewrite… Read More »
Altering the sequence of fields of a table was a feature I was looking for in OpenOffice Base. It is not directly possible to drag the columns or fields and alter their sequence. We need a sql workaround to change the order of the columns. Lets say the sequence or order of the columns is… Read More »
By default Apache puts all the web files into a single directory (commonly /var/www). If there are multiple users on a system then every user can have his own web directory to store the web files. userdir is the Apache module which enables each user to have a separate directory to store web files. This… Read More »
Client IP address Php applications are mostly web based and often need to get the ip address of the user who is connecting to the application. Ip address is required for various logging purpose, geolocation service etc. The most common way to get the ip address of a remote user is by using the superglobal… Read More »
Till recently most of my php scripts were working fine on the servers with instantaneous outputs as and when a echo statement was encountered. Output in Chunks One issue that popped a lot on localhost was that of chunky outputs; that is the outputs of big scripts came out in chunks rather than smoothly with… Read More »
Remote login with CURL The curl extension of php can be used to open remote webpages by both GET and POST methods. There are many situations when you need a php script to login into a website and open a certain page. For example when you are writing a bot or web scraper. To login… Read More »
wxpython While executing a wxpython script if a error occurs then a white window popups with some message, and it disappears fast enough before it can be read. So here is a fix to pause it and read it what and where the error in the code is : app = wx.App(redirect=False) MyFrame(None).Show() app.MainLoop() The… Read More »
Database applications written in php often need to export data for reporting purpose. A popular export format is excel. Excel is a spreadsheet that lays out data in a grid format. Excel itself is a microsoft proprietory format. There are many libraries available for php like Spreadsheet_Excel_Writer pear package etc that can do the job…. Read More »
The SQL Script should have comments starting with – or — only on new lines and each command should end with a ; . Reading a sql file and putting all of it in a string variable and feeding to the execute command would result in an exception. All instructions must be executed individually. A… Read More »
Configuration files are used in applications to store settings, user preferences and other configuration parameters of an application so that. When configurations are changed from within the application these need to be saved so that next time the application starts with these new settings. In Java reading and writing to a configuration is pretty simple… Read More »
Raw sockets with winpcap A previous post explains how to send on windows xp. However the winsock api has limited raw socket support in windows versions greater than windows xp+sp1. Therefore winpcap has to be used to send raw packets on higher windows versions. Winpcap is a packet driver useful for packet capturing and sending… Read More »
Port Scanning Port Scanning searches for open ports on a remote system. The basic logic for a portscanner would be to connect to the port we want to check. If the socket gives a valid connection without any error then the port is open , closed otherwise (or inaccessible, or filtered). TCP Port Scanning Drawbacks… Read More »
Hack bsnl broadband username and passwords Bsnl Broadband continues to grow as one the most popular broadband services in India with high speed facilities of upto 2 mpbs. But a large number of users of this service are vulnerable to hacker attacks because discovering and hacking the vulnerable victims of this network is shockingly simple…. Read More »
DNS Query When we type a web url or domain in our browser a dns request is immediately send by our browser to a DNS server to get the IP address of that web address. In winsock applications we achieve this by gethostbyname() and things are pretty simple. In this article we shall do this… Read More »
Winsock packet sniffer A packet sniffer is a program that can sniff the packets moving on the network. All applications communicate over the network with data packets where each packet contains part of the whole data being exchanged. A sniffer is able to pickup these individual packets and read them. In this post we are… Read More »
Raw sockets using winsock Raw sockets or “Raw Packets”, enable a program to access the entire contents of a packet or datagram, both for reading and writing purpose. In other words, you can fabricate a whole packet according to your likes and dislikes. For example, a TCP packet would contain an IP header, a TCP… Read More »