IEEE 802.11 IEEE 802.11 is a set of media access control (MAC) and physical layer (PHY) specifications for implementing wireless local area network (WLAN) computer communication in the 2.4, 3.6, 5 and 60 GHz frequency bands. They are created and maintained by the IEEE LAN/MAN Standards Committee (IEEE 802). The base version of the standard was released in 1997 and has had subsequent amendments. The standard and amendments provide the basis for wireless network products using the Wi-Fi brand. While each amendment is officially revoked when it is incorporated in the latest version of the standard, the corporate world tends to market to the revisions because they concisely denote capabilities of their products. As a result, in the market place, each revision tends to become its own standard. The LinksysWRT54G contains a router with an 802.11b/g radio and two antennae General description[edit] History[edit] 802.11 technology has its origins in a 1985 ruling by the U.S. Protocol[edit] 802.11b[edit]
An introduction to Linux socket and network Application Programming Interface (API) functions unsigned long int INADDR_LOOPBACK You can use this macro constant to stand for the ''address of this machine'' instead of finding its actual address.It is the Internet address '127.0.0.1', which is usually called 'localhost'. This special constant saves you the trouble of looking up the address of your own machine.Also, the system usually implements INADDR_LOOPBACK specially, avoiding any network traffic for the case of one machine talking to itself. unsigned long int INADDR_ANY You can use this macro constant to stand for ''any incoming address'' when binding to an address. unsigned long int INADDR_BROADCAST This macro constant is the address you use to send a broadcast message. unsigned long int INADDR_NONE This macro constant is returned by some functions to indicate an error. Host Address Functions - Functions to operate on them These additional functions for manipulating Internet addresses are declared in 'arpa/inet.h'. int inet_aton(const char *name, struct in_addr *addr) The API Details
How to safely connect from anywhere to your closed Linux firewall In general all the great ideas are the simple ones. Many times we see a great idea in practice and we wander why didn’t we thought of that before? It is just so simple… The first time I have seen the knockd project I liked it instantly. The idea is so simple, and though so effective. How does a port knocker work? we install the port knocker daemon on our server (knockd)we configure some port sequences (tcp, udp, or both), and the appropriate actions for each sequence.the knockd daemon will be running in the background, at low level passively on the network interface. To exemplify its power I will show a scenario with a server running a firewalled ssh port that allows connections only from one static management IP. Installing knockd First you will need to install the knockd daemon. apt-get install knockd Our closed firewall setup: we will use a closed SSH setup that allows connections only from 192.168.0.100 to our server. knock -v 192.168.0.102 7000 8000 9000 Automatically close rules:
High-speed multimedia radio Basics[edit] Capabilities[edit] HSMM can support most of the traffic that the Internet currently does, including video chat, voice, instant messaging, the Web (HTTP), file transfer (FTP), and forums. The only differences being that with HSMM, such services are community instead of commercially implemented and it is mostly wireless. Frequencies and channels[edit] The following is a list of the 802.11 channels that overlap into an amateur radio band under the FCC in the United States. The following images show the overlapping relationship of the Part 15 unlicensed bands and the Part 97 licensed bands. 2.4 GHz 802.11b/g 5.8 GHz 802.11a Acronyms Used: (amateur radio) (ISM) (Radar) Channels and power[edit] 802.11a[edit] The 802.11a amateur radio band consists of twelve non-overlapping channels in the 5.650–5.925 GHz (5 cm) band. 802.11b[edit] The 802.11b amateur radio band consists of eight overlapping channels in the 2.390–2.450 GHz (13 cm) band. 802.11g[edit] 802.11n[edit] Frequency sharing[edit]
Packet Sniffer Code in C using Linux Sockets (BSD) #include<netinet/in.h> #include<errno.h> #include<netdb.h> #include<stdio.h> //For standard things #include<stdlib.h> //malloc #include<string.h> //strlen #include<netinet/ip_icmp.h> //Provides declarations for icmp header #include<netinet/udp.h> //Provides declarations for udp header #include<netinet/tcp.h> //Provides declarations for tcp header #include<netinet/ip.h> //Provides declarations for ip header #include<netinet/if_ether.h> //For ETH_P_ALL #include<net/ethernet.h> //For ether_header #include<sys/socket.h> #include<arpa/inet.h> #include<sys/ioctl.h> #include<sys/time.h> #include<sys/types.h> #include<unistd.h> void ProcessPacket(unsigned char* , int); void print_ip_header(unsigned char* , int); void print_tcp_packet(unsigned char * , int ); void print_udp_packet(unsigned char * , int ); void print_icmp_packet(unsigned char* , int ); void PrintData (unsigned char* , int); FILE *logfile; struct sockaddr_in source,dest; int tcp=0,udp=0,icmp=0,others=0,igmp=0,total=0,i,j; int main() struct sockaddr saddr;
Web Server Survey Archives In the April 2014 survey we received responses from 958,919,789 sites — 39 million more than last month. Microsoft made the largest gain this month, with nearly 31 million additional sites boosting its market share by 1.9 percentage points. IIS is now used by a third of the world's websites. More than 70% of this month's new IIS-powered websites are hosted in the US, followed by 22% in China. Many of the new IIS sites hosted by Nobis Technology Group feature similar content and form part of a Chinese link farm. In terms of active sites, Apache remains in a much stronger position with a 52% share of the market, compared with Microsoft's 11%. Apache also fares well amongst the million busiest sites, where there is intrinsically very little interference from domain holding pages, link farms and other web spam. The latest version of Apache (2.4.9) was released on March 17. The stable branch of nginx was updated twice during March. Active sites Other (more...)
Invent Your Own Computer Games with Python - Chapters Chapter 1 Read online: Chapter 1 - Installing Python Videos: Chapter 2 Read online: Chapter 2 - The Interactive Shell Chapter 3 Read online: Chapter 3 - Strings Download source: hello.py Copy source to clipboard: Use the online diff tool to find typos in your code: hello.py Chapter 4 Read online: Chapter 4 - Guess the Number Download source: guess.py Use the online diff tool to find typos in your code: guess.py Chapter 5 Read online: Chapter 5 - Jokes Download source: jokes.py Use the online diff tool to find typos in your code: jokes.py Chapter 6 Read online: Chapter 6 - Dragon Realm Download source: dragon.py Use the online diff tool to find typos in your code: dragon.py Chapter 7 Read online: Chapter 7 - Using the Debugger Chapter 8 Read online: Chapter 8 - Flow Charts Chapter 9 Read online: Chapter 9 - Hangman Download source: hangman.py Use the online diff tool to find typos in your code: hangman.py Chapter 10 Read online: Chapter 10 - Tic Tac Toe Download source: tictactoe.py Chapter 11 Download source: bagels.py
Packet Capture and Analayzer Download source files - 364 Kb Introduction The first idea of writing a packet sniffer program came from a reply to my comments on one of the projects named "NetSend ( Sending popup messenger messages between computers )" by Marc Clifton. Marc asked me "What about receiving message". To say the truth, I didn't know how I could do that. I knew a program which I had downloaded and tested years ago. After previewing the WinPCap source code , my first trial was to write a wrapper class for it. First I traced the packets captured by Etheral and built some protocols and was able to display them in my test program. Project contents Pacanal name comes from PACket ANALyzer. ColumnSorter This class enables to sort list view items. Requirements To run the code you need to have those below: Windows NT / 2K / XP A PC with an Ethernet card (LOL) NDIS packet capture driver (npf.sys) installed npf.sys can be downloaded from the site which is the one I used. Warning Conclusion
Hacking Illustrated: Hacking and Computer security videos Phreaknic 12 (2008) Hacker Con This is a quick and dirty video documentary of the things that when on around the talks and event at Phreaknic 12 (2008). Don't watch if you get sick at shaky cam movies like Blair Witch or Cloverfield. A rough timeline of the content in the video is as follows: Intro and leaving Louisville with Brian.
Advanced Programming Languages Introduction Research Syntax Semantics Static Semantics ( Type Theory ) Dynamic Semantics Semantic Related Developments Abstract Interpretation Program Transformation Decompilation Partial Evaluation Pragmatics ( Software Patterns , Generic Programming , Visual Programming , Persistence , Reflectiveness , Hyperprogramming) Semiotics Implementation Techniques: Garbage collection , Abstract Machines Some Conferences (not updated) People and Groups Teaching Introduction to Programming Languages Selecting First Programming Language Courses about Programming Languages Courses about Foundations of Programming Languages Courses about Language Processors Paradigms Comparing Programming Languages Functional Programming ( Haskell, ML) Logic Programming (Prolog) Object Oriented Programming (Java, C++, Smalltalk, ...) Cross Paradigms : Logic-Functional , Object Oriented-Functional , Object Oriented-Logic My List of Programming Languages Selected Bibliography Selected Papers Selected Books Acknowledgments Backus Naur Form (BNF) C.
Ch14 : Linux Firewalls Using iptables Network security is a primary consideration in any decision to host a website as the threats are becoming more widespread and persistent every day. One means of providing additional protection is to invest in a firewall. Though prices are always falling, in some cases you may be able to create a comparable unit using the Linux iptables package on an existing server for little or no additional expenditure. This chapter shows how to convert a Linux server into: A firewall while simultaneously being your home website's mail, web and DNS server. Creating an iptables firewall script requires many steps, but with the aid of the sample tutorials, you should be able to complete a configuration relatively quickly. Originally, the most popular firewall/NAT package running on Linux was ipchains, but it had a number of shortcomings. Better integration with the Linux kernel with the capability of loading iptables-specific kernel modules designed for improved speed and reliability. In this example:
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