Winpcap Winpcap is a packet capture library for Windows used for packet sniffing and sending raw packets. Wireshark is a popular sniffer tool that uses winpcap to sniff packets. Here is a sample code which shows how winpcap can be used to sniff incoming packets on a particular interface. Code /* Simple Sniffer with winpcap… Read More »
MAC Address Mac address (Media Access Control Address) or hardware address is a 48 bit (6 character) wide address assigned to a network interface. It is important for the packet delivery between 2 devices like your computer and the router. Ethernet protocol uses the mac address to deliver it to the right network node. It… Read More »
The traceroute utility can be installed from synaptic : $ sudo apt-get install traceroute Some Information : $ traceroute -V Modern traceroute for Linux, version 2.0.15, Oct 17 2010 Copyright (c) 2008 Dmitry Butskoy, License: GPL v2 or any later Doing some test runs $ traceroute www.google.com traceroute to www.google.com (74.125.235.20), 30 hops max, 60… Read More »
Socket applications often need to convert hostnames like google.com to their corresponding ip address. This is done through dns requests. The socket api in linux provides functions like gethostbyname and getaddrinfo that can be used to perform the dns requests and get the ip address. 1. gethostbyname The first method uses the traditional gethostbyname function… Read More »
MPM (Multi processing module) is a component of apache server, that determines how multiple clients or connections shall be handled. Apache is flexible by design and there are different mpms that can be used with apache depending on the needs. Some MPMs create a separate process to handle each request, whereas some create separate threads…. Read More »
Linux distro name and version When working with an unknown server, the first task of a sys admin is to gather some information about the system, like what OS is it running, what version, what services are running and so on. And there is no single command that can detect distribution specific information consistently across… Read More »
Install mpm itk On ubuntu mpm itk can be installed from synaptic. Look for the package called apache2-mpm-itk sudo apt-get install apache2-mpm-itk Configure Configuration for mpm itk can be done in the file sites-enabled/000-default $ gksudo gedit /etc/apache2/sites-enabled/000-default In the VirtualHost *:80 section add this just before the end of the VirtualHost tag [xml] <IfModule… Read More »
The html5 file api provides lots of new features which can be used to read files on clientside from within the browser. Lets take a look at this Demo first : This file upload control will only take zip or png files which are less than 1MB in size. For any other files it will… Read More »
The simplexml extension of php is quite simple and easy to use when it comes to parsing “well-formatted” xml files. Well formatted means , xml that is not broken or does not have too many errors. One of the most handy functions of this extension is simplexml_load_string. Here is an example : <?php $xml =… Read More »
In the previous part we made a simple sniffer which created a raw socket and started receiving on it. But it had few drawbacks : 1. Could sniff only incoming data. 2. Could sniff only TCP or UDP or ICMP or any one protocol packets at a time. 3. Ethernet headers were not available. In… Read More »
Packet Sniffer Sniffers are programs that can capture/sniff/detect network traffic packet by packet and analyse them for various reasons. Commonly used in the field of network security. Wireshark is a very common packet sniffer/protocol analyzer. Packet sniffers can be written in python too. In this article we are going to write a few very simple… Read More »
MPDF Many php applications need to create pdf of documents like invoice , receipt and even id card etc. In this article we shall create a pdf invoice using the mpdf pdf creation library. Mpdf is made in php without any other external library. Mpdf parses css much better than any other free pdf libraries… Read More »
Packet Sniffer Example of a packet sniffer is Wireshark. Packet sniffers pick up the packets going in and out of a system and analyse them and present them to user for further analysis. In this post we are going to code a simple packet sniffer in php. The basic theory this packet sniffer is that… Read More »
Php functions like zip_open return an error number if they fail. To get the corresponding error message from the error number , use the following function. function zip_error_message($errno) { // using constant name as a string to make this function PHP4 compatible $zipFileFunctionsErrors = array( 'ZIPARCHIVE::ER_MULTIDISK' => 'Multi-disk zip archives not supported.', 'ZIPARCHIVE::ER_RENAME' => 'Renaming… Read More »
When a browser makes a request to a php script, the browser sends some http headers which can look like this : Host: localhost Connection: keep-alive User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/15.0.874.121 Safari/535.2 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: UTF-8,*;q=0.5 Cookie: username=admin; password=21232ffc3; PHPSESSID=o5m4e2td1m66c4pkjdag9vs0u2 The php script under request ,… Read More »
In this article we are going to login into Google Adsense and retrieve earnings. Google Adsense now has a new interface and so needs a different kind of coding. In this example we shall fetch “yesterday’s” earnings sitewise. Create a Report to be fetched : First open the sitewise report in the Performance Tab in… Read More »
PHP has a useful function called dns_get_record that can be used to get different types of records for a give domain , very easily. These include the nameserver records, A records, CNAME records, MX records, SOA records etc. The following examples are using the interactive shell, but you would use the function the same way… Read More »
PHP Handlers PHP handlers are a link between a webserver(say Apache) and the PHP libraries. PHP handlers enable a webserver to load the PHP library in a certain manner and execute the PHP code and return the output to the webserver. There are many different kind of PHP handler setups available. Each has its own… Read More »
Suphp Suphp php handler is an apache module (mod_suphp) that runs php scripts with ownership and permission of a specific user. This is seen as a security enhancement since the system can keep track of which user’s php script is running (and causing problems if any). In shared hosting environments suphp is very popular since… Read More »
Monitor the network bandwidth used by each process with nethogs command on Linux