Group16_QuadMasters:Remote Login

Remote login requires three basic components:

1. Software download

2. Internet connection

3. Secure desktop sharing network


For remote login to work, both the host computer and all remote users have to download and install the same desktop sharing software. Desktop sharing software typically includes two distinct programs:

1. The desktop sharing client that runs on the host computer

2. A viewer program that allows the remote user to view the contents of the host computer's desktop in a resizable window

Group8_Vintageboys:TCPdump

As said previously, tcp dump is an analyser tool which displays the packets which flow in a network or an interface in a computer or a server(which analyses the packets which the server is using) and displays them.
It allows us to view entire ethernet frame or other link layer and if required print the frame header. By default, tcp dump prints the packets at the IP layer.
TCPdump generally helps in solving a variety of problems and analysts say that the number of server based problems that could be solved by using TCPdump is limitless since it prints detailed information about network traffic, helps in debug denial and during service attacks. If a network is flooded and all other attempts to determine the source or destination of the traffic fail, tcpdump will show you the source address, destination address, and type of traffic involved.

MKN_Folks...SOS Need Ur help!

Yup! This is "ejjactly" how I felt when I saw your neat little blogs, children, on our CN Blog Site! Why, that mammoth look of frustration? The sheer volume of the number of blogs to read and evaluate! 

Thought that the hyperlinks to your blogs will fit in one page, neatly on the left hand side. Each of us faculties need read only a max of 5 blogs of groups we are handling. By the way, saw the blogs on 5 B's Home Page (http://netbrainz.blogspot.com/) ? 

Pretty neat...Has a lot of YouTube Videos on some good sensible "fundas" on Networking :-)

Well, to say the least, I think Iam waaaaaaaay too short-sighted as well as did not foresee the avalance of information you folks would collect and post! Maybe under-estimated the energy and enthusiasm inherent in your present chronological age, dear students! I ADMIT :-) 

Therefore, this blog. I need help, ideas to make it more manageable. Could someone volunteer to help me? I will give admin rights to your gmail id, so you could implement your ideas of helping me. Its SOS considering the amount of blogs that will be logged every lab! Do email me mydhili.nair@gmail.com  with any of your ideas, okies? Looking forward to your co-operation, folks!:-)

---Mydhili

 

Group12_chaarMusafirs:how does internet works?

The Internet is a global network of computers that connects millions of people and uses the Internet Protocol Suite (TCP/IP) standard rules for data representation, signaling, authentication, and error detection. Each computer connected to the Internet must have a unique address. Internet addresses are in the form nnn.nnn.nnn.nnn where nnn must be a number from 0 - 255. This address is known as an IP address. Once a laptop or computers is connected to any routers or servers then IP addresses is automatically assigned to them. If we want to access the web server then we take the help of DNS(domain name service)server. If we type www.google.com then it connects to the Google DNS server and match the IP address of searched item and display the searched items on the page.

Group12_ChaarMusafirs : Protocol Stack and addressing

Our project will describe the several protocols in details, and put forth comparisons (for eg. With the OSI reference model) Our goal is to analyze data from a live network or from a capture file on disk, and examine details of the packets transmitted and the protocols used. Our program of choice for the network analysis is Wireshark(formerly ethereal) and N map. We plan to host dummy networks, and transfer files, download torrents, P2P programs and host game servers which will be then be monitored by these tools. Also, our project will delve into the details of how Ipv4, Ipv6 addresses are assigned over the network, how the Address Resolution Protocol (ARP) is used for finding a host's link layer (hardware) address/MAC address. and how through DHCP (Dynamic Host Configuration Protocol) lets a network administrator supervise and distribute IP addresses from a central point, with respect to local networks/Routers (we will use Linkysys WRT54AG router for testing) and even the Internet as a whole.

Linksys WRT45ABG


Nmap:

group06_Bandwidth Brothers : Transmission Media

Transmission media is the state which propagates energy waves. The state may be solid,liquid or gas. Our team will stress more on transmission media in networking as it is will be more useful for our subject. In our talk we would like to show visually the media type categories if possible and talk about it. The three main media type categories according to us are copper cable ( like coaxial cable), wireless ( such as microwaves used in LAN,infrared) and finally fibre optics (most expensive among the three). According to us none of them can be considered “the best” cause each has different use in different situation. So according to the need or situation we have to choose the best media. Also suppose if one fails we must have another to back upon, cause if events such as earthquake occurs if one media fails to work the other must be ready to use.We will be focussing mainly on the five traditionally used transmission media and explain everything related to it in detail. We would also rate the performance of they types of transmission media after thorough analysis. We would also like to download applications of transmission media and give a small demonstration. The basic understanding of transmission media will provide a good base for students studying computer communication. So to make everyone understand the basics of transmission media would be our team’s main aim. The five main transmission media which we will be focussing is twisted pair(used for voice applications), coaxial cable, microwave, satellite and finally fibre.

Group05_Illuminati:Transmission Media

On any network, the various entities must communicate through some form of media. Just as humans can communicate through telephone wires or sound waves in the air, computers can communicate through cables, light, and radio waves. Transmission media enable computers to send and receive messages but do not guarantee that the messages will be understood.
Our project will discuss some of the most common network transmission media, such as coaxial cable, shielded twisted-pair cable, and unshielded twisted-pair cable. We will also learn about network fiber-optic cable and wireless communications.

GROUP3_AMAK: Network protocol analysis

Network protocols defines a language of rules and conventions for communication between network devices.

List of Protocols with examples of each : -

1 Layer 1 protocols (Physical Layer)

• ADSL Asymmetric digital subscriber line
• ISDN Integrated Services Digital Network

2 Layer 2 protocols (Data Link Layer)

• Ethernet
• IEEE 802.11
• IEEE 802.16

Layer 3 protocols (Network Layer)

• IPv4 Internet Protocol version 4
• IPv6 Internet Protocol version 6

Layer 4 protocols (Transport Layer)

• TCP Transmission Control Protocol
• UDP User Datagram Protocol

Layer 5 protocols (Session Layer)

• NCP NetWare Core Protocol
• NFS Network File System

Layer 7 protocols (Application Layer)

• FTP, File Transfer Protocol
• HTTP, HyperText Transfer Protocol
• IMAP, Internet Message Access Protocol
• POP3 Post Office Protocol Version 3
• Telnet, a remote terminal access protocol
• SOAP, Simple Object Access Protocol

What is Network Protocol Analysis and Protocol Analyzer?

The packet analyzer (also known as a network protocol) is computer software or computer hardware that can intercept and log traffic passing over a digital network or part of a network.

Network protocol analysis is a process for a program or a device to decode network protocol headers and trailers to understand the data and information inside the packet encapsulated by the protocol. To conduct protocol analysis, packets must be captured at real time for line speed analysis or later analysis. Such program or device is called a Protocol Analyzer.

The uses of network analysers :

• Analyze network problems
• Detect network intrusion attempts
• Gain information for effecting a network intrusion
• Monitor network usage
• Gather and report network statistics
• Filter suspect content from network traffic
• Spy on other network users and collect sensitive information such as passwords
• Debug client/server communications
• Debug network protocol implementations

Notable Network analysis applications : -

• dSniff
• Microsoft Network Monitor
• Wireshark (formerly known as Ethereal)
• Snoop (part of Solaris)
• OPNET Technologies ACE Analyst

Group13_Avani:Protocol stack and addressing

A protocol stack/communication stack is a particular software implementation of a computer networking protocol suite.
The Open System Interconnection Reference Model (OSI Reference Model or OSI Model) is an abstract description for layered communications and computer network protocol design. It is a prescribed hierarchy of software layers, starting from the application layer at the top to the physical layer at the bottom. The stack resides in each client and server.

OSI MODEL

LAYER -FUNCTION

7. Application -Network process to application

6. Presentation -Data representation and encryption

5. Session -Interhost communication

4. Transport -End-to-end connections and reliability

3. Network -Path determination and logical addressing

2. Data link -Physical addressing

1. Physical -Media, signal and binary transmission

A client application sends data down its protocol stack, passing through each of the protocols and interfaces. At the receiving side, the data packets traverse a similar stack of protocols and programs, this time in reverse. Starting at the physical layer, the packet passed through each successive layer until it reaches the top of the stack at the relevant application process. At each layer, the information appended by the different protocols is examined so that the host can forward the packet to its final destination. For the host to accomplish this, both the client and the host need to run the same program at each level.
To deliver data between two Internet hosts, it is necessary to move data across the network to the correct host, and within that host to the correct user or process. One of the schemes used by TCP/IP to accomplish these tasks is protocol stack addressing which deliver data to the correct host.
Specification used for multiple protocol stack addressing are:
• Media Access Control (MAC) driver: This is a device driver written by the vendors of the NIC that directly interfaces with the NIC hardware.
• Upper-Level Protocol driver
• Protocol manager program
To avoid confusion with MAC addresses, which are machine or station addresses, the term IP address will be used to designate this kind of address.Since the network and data link layer use different addressing schemes, some system is needed to convert or map the IP addresses to the MAC addresses. Transport-layer services and user processes use IP addresses to identify hosts, but packets that go out on the network need MAC addresses. The Address Resolution Protocol (ARP) is used to convert the 32-bit IP address of a host into its 48-bit MAC address. When a hosts wants to map an IP address to a MAC address, it broadcasts an ARP request on the network, asking for the host using the IP address to respond. The host that sees its own IP address in the request returns its MAC address to the sender. With a MAC address, the sending host can transmit a packet on the Ethernet and know that the receiving host will recognise it.

Group3_AMAK: How internet works?

The internet is a standardized, global system of interconnected computer networks that connects millions of people. The system uses IP/TCP standard rules for data representation. It carries a vast array of information resources and services in the form of interlinked hyper text documents of the world wide web(www) and the infrastructure to support electronic mail.

As we know that the internet is a global network of computers, each computer must have a unique address in the form of nnn.nnn.nnn.nnn where nnn ranges between 0-255. This unique address is known as IP address. If you connect to internet through an Internet Service Provider(ISP), you are assigned a temporary IP address for the session. If you connect to the internet through LAN(Local Area Network) you might be assigned a permanent IP address or a temporary one from DHCP(Dynamic Host Configuration Protocol) server.
Once the computer is connected to the internet and we want to communicate with the other computers, the message must be translated from alphabetic text to electronic signals and is sent over the medium through which it is connected. The receiving computer translates it back into alphabetic text and this is achieved through the use of protocol stack.The protocol stack used on the internet is referred to as TCP/IP protocol stack.

The protocol stack consists of layers that have different functions:

1.)Application Protocols layer: it is the protocol which is specific to the applications such as WWW,FTP,E-Mail.etc.
2.)Transmission Control Protocol Layer: directs packets to a specific application on a computer using a port number.
3.)Internet Protocol Layer: it directs packets to a specific computer using IP address.
4.)Hardware Layer: Converts binary packet data into network signals and back.

The data to be transmitted works its way downward the stack. The data to be transmitted is broken into smaller chunks of data known as packets.Each packet is assigned a port number.Port numbers are necessary because we need to determine the program on the computer which requires the information.From the TCP layer the packets proceed to the IP layer where they are assigned a destinatin IP address. Now that the packet has the port number and the IP address it proceeds to the hardware layer where it becomes ready to be sent over the internet. The packets work their way upwards in the protocol stack at the receiving computer. When the data reaches the top of the stack the data is reassembled in its original form.

The DNS is a distributed database which keeps track of computer's names and their corresponding IP addresses on the Internet. Many computers connected to the Internet host part of the DNS database and the software that allows others to access it. These computers are known as DNS servers. No DNS server contains the entire database; they only contain a subset of it. If a DNS server does not contain the domain name requested by another computer, the DNS server re-directs the requesting computer to another DNS server.

Group4_Newcreation:Network Protocal Analysis

Network protocol analysis is a process for a program or a device to decode network protocol headers and trailers to understand the data and information inside the packet encapsulated by the protocol. To conduct protocol analysis, packets must be captured at real time for line speed analysis or later analysis. Such program or device is called a Protocol Analyzer.network protocol defines a language of rules and convention for communication between network devices.
Network protocols include mechanisms for devices to identify and make connections with each other, as well as formatting rules that specify how data is packaged into messages sent and received. Some protocols also support message acknowledgement and data compression designed for reliable and/or high-performance network communication. Hundreds of different computer network protocols have been developed each designed for specific purposes and environments.
Internet Protocols:
The Internet Protocol family contains a set of related (and among the most widely used network protocols. Besides Internet Protocol (IP) itself, higher-level protocols like TCP, UDP, HTTP and FTP all integrate with IP to provide additional capabilities. Similarly, lower-level Internet Protocols like ARP and ICMP also co-exist with IP. These higher level protocols interact more closely with applications like Web browsers while lower-level protocols interact with network adapters and other computer hardware.
How Network Protocols Are Implemented:
Modern operating systems like Microsoft Windows contain built-in services or daemons that implement support for some network protocols. Applications like Web browsers contain software libraries that support the high level protocols necessary for that application to function. For some lower level TCP/IP and routing protocols, support is implemented in directly hardware (silicon chipsets) for improved performance.

Group05_Illuminati:How Internet Works?

Internet is a global network of computers. Every computer that is connected to the Internet is part of a network. For example, a modem can be used to dial a local number to connect to an Internet Service Provider (ISP). At work, a local area network might be used but still connection to the Internet is made using an ISP that the company has contracted with. When a connection to an ISP is made, we become part of their network. The ISP may then connect to a larger network and become part of their network. The Internet is simply a network of networks.
Each computer connected to the Internet must have a unique address. This address is known as an IP (Internet Protocol) address. Every computer needs one to communicate on the Internet and it is usually built into the computer's operating system. The Internet uses a protocol stack referred to as the TCP/IP protocol stack because of the two major communication protocols used.The Internet backbone is made up of many large networks which interconnect with each other. These large networks are known as Network Service Providers or NSPs.These networks peer with each other to exchange packet traffic. Each NSP is required to connect to three Network Access Points or NAPs. At the NAPs, packet traffic may jump from one NSP's backbone to another NSP's backbone. NSPs also interconnect at Metropolitian Area Networks or MAEs. MAEs serve the same purpose as the NAPs but are privately owned. NAPs were the original Internet interconnect points. Both NAPs and MAEs are referred to as Internet Exchange Points or IXs. NSPs also sell bandwidth to smaller networks, such as ISPs and smaller bandwidth providers.The ISP maintains a pool of modems for their dial-in customers. This is managed by some form of computer (usually a dedicated one) which controls data flow from the modem pool to a backbone or dedicated line router. This setup may be referred to as a port server, as it 'serves' access to the network. Billing and usage information is usually collected here as well. No computer knows where any of the other computers are, and packets do not get sent to every computer. The information used to get packets to their destinations are contained in routing tables kept by each router connected to the Internet.. A router is usually connected between networks to route packets between them. Each router knows about it's sub-networks and which IP addresses they use. When a packet arrives at a router, the router examines the IP address put there by the IP protocol layer on the originating computer. The router checks it's routing table. If the network containing the IP address is found, the packet is sent to that network.After your packets traverse the phone network and your ISP's local equipment, they are routed onto the ISP's backbone or a backbone the ISP buys bandwidth from. From here the packets will usually journey through several routers and over several backbones, dedicated lines, and other networks until they find their destination,

Group18_awesum4sum: Undersatnding Computer Networks

Earlier a single computer served the whole organization's computational needs. But now a large number of seperate computers are capable of working individually and get the tasks done. But all these individual computers should be able to share and exchange the data and information in order to complete the organizational needs. This is possible by interconnecting the computers. These systems are called Computer Networks. There are two ways to communicate in a network. It can be a broadcast network, where a single communication channel is shared by all networks. The data is sent by any one of the system and any other system receives it. The system checks if the packets are intended for itself, if yes, it accepts the packets or it ignores. The data can also be sent to all the systems in the network. We can also have point to point networks, where there exists many computers between the source and the destination.

Group8_VintageBoys:TCPDump

TCPDUMP is a network protocol analyser which works on command line.it is the pre version of network protocol analysers like ethereal and wireshark

TCP Dump allows you to examine the header or content of each packet flowing over an interface or data link. To begin monitoring, select the desired interface from the "Monitor interface" popup and press "Start".

TCP Dump in IPNetMonitorX is a simple User Interface to the underlying unix "tcpdump" facility. Unix tcpdump has many options allowing you to specify in detail what packets you want to capture including protocols, interfaces, and link layer headers. The Options field accepts standard tcpdump options ("-n -p -t" for example to show numeric addresses, do not set promiscuous mode, and no time stamps).

Naturally you can run tcpdump directly from a terminal window if desired. The reason to incorporate TCP Dump in IPNetMonitorX is simple user convenience.

While TCP Dump is well suited to capturing packet headers and protocol information, it is less ideal for viewing the actual TCP data flow between a client and server. For this purpose, you can "Use TCP Flow" instead of TCP Dump. tcpflow is an open source utility distributed under GNU .

picture source-

http://sustworks.com/site/prod_ipmx_help/html/TCPDumpHelp.html

The grab of TCPDUMP from ethereal

tcpdump is used on platforms like ethereal by network professionals for troubleshooting, analysis, software and protocol development. It has all of the standard features you would expect in a protocol analyzer, and several features not seen in any other product. Its open source licence allows people in the networking community to add enhancements. It runs on all popular computing platforms, including Unix, Linux, and Windows.although the windows version is enhanced with ethereal modern day network analyzers like wireshark are more popular and have made it redundant.


abridged from-http://www.ethereal.com/
parisparfait.typepad.com

Group 10 _Fosters:understanding on computer networks

Computer network is basically concerned with a group of interconnected computers to share information and data.

The above are the basic types of network used to connect computers.
the general types of computer networks are

Local area network (LAN) The computers are geographically close together (that is, in the same building).

Wide area network (WAN): The computers are farther apart and are connected by telephone lines or radio waves.

Camps area network (CAN): The computers are within a limited geographic area, such as a campus or military base.

Metropolitan area network (MAN) A data network designed for a town or city.

Home area networks (HAN): A network contained within a user's home that connects a person's digital devices.

Connections can be either wired or wireless (eg :bluetooth) depending upon our convenience.They can be intra connected using wires, hubs , routers and various different hardware components .

group9_dead lock: IP utilities/ tcpdump

IP(Internet Protocol) is the primary network protocol allows us to create very large Internetwork by connecting individual networks together. when we send data between devices on different network, The data is routed between networks using IP. This permits us to view even a huge Internet work such as global Internet as if it were just a single large network. IP function at layer of OSI model it can therefore run on different data link interface including Ethernet and Wi-Fi. data on IP network is organized into packets. each packet includes both a header(source, destination and other information about data) and message itself.
IP/TCP three layers:-
* IP - its responsible for moving packet of data from node to node. IP forwards each packets based on a four byte destination address( IP number). IP operates on gateway machine that move data from department to organization to region and then around the world.
* TCP(transmission control protocol) - its responsible for verifying correct delivery of data from client to server. data can be lost in the intermediate network. TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received.
* Sockets - its a name given to the packages of subroutines that provide access to TCP/IP on most systems.

group7_rothman:Transmission media

Transmission Media describes the type of physical system used to carry a communication signal from one system to another. Examples of transmission media include twisted-pair cable, coaxial cable, and fiber optic cable.

There are 2 basic categories of Transmission Media:

1. Guided
2. Unguided

Guided Transmission Media uses a "cabling" system that guides the data signals along a specific path. The data signals are bound by the "cabling" system. Guided Media is also known as Bound Media. Cabling is meant in a generic sense in the previous sentences and is not meant to be interpreted as copper wire cabling only.

There 4 basic types of Guided Media:

Open Wire
Twisted Pair
Coaxial Cable
Optical Fiber

Unguided Transmission Media consists of a means for the data signals to travel but nothing to guide them along a specific path. The data signals are not bound to a cabling media and as such are often called Unbound Media. The three guided media commonly used for transmission are twisted-pair,coaxial and fiber optic cable.

Unguided media,transmission and reception are achieved by means of an antenna.

The various types of waves used for wireless transmission are:

Terrestrial microwave

Satellite microwave

Broadcast radio

Infrared

Wireless propagation is through one of the following routers:

-Ground wave

-Sky wave

-Light of sight

Group 10_Fosters:IP/TCP

IP/TCP

TCP/IP defines the rule computers must follow to communicate with each other over the internet. It is the protocol suite that drives the Internet. Specifically, TCP/IP handles network communications between network nodes (computers, or nodes, connected to the net).The suite is actually composed of several protocols including IP which handles the movement of data between host computers, TCP manages the movement of data between applications.

About IP

IP is for communication between computers.It is a "connection-less" communication protocol. IP does not occupy the communication line between two computers. IP reduces the need for network lines. Each line can be used for communication between many different computers at the same time.With IP, messages (or other data) are broken up into small independent "packets" and sent between computers via the Internet.

IP is responsible for "routing" each packet to the correct destination.When an IP packet is sent from a computer, it arrives at an IP router. The IP router is responsible for "routing" the packet to the correct destination, directly or via another router.

About TCP

TCP is for communication between applications.If one application wants to communicate with another via TCP, it sends a communication request. This request must be sent to an exact address. After a "handshake" between the two applications, TCP will set up a "full-duplex" communication between the two applications.The "full-duplex" communication will occupy the communication line between the two computers until it is closed by one of the two applications.

Group16_QuadMasters:Remote Login

In the 1970s and early 1980s, text-oriented terminals were the predominate tools for computer users. Protocols such as TELNET and RLOGIN were developed for terminal users to use their terminals as if they were directly connected to a remote system. UNIX systems, with their predominately terminal-oriented interface, still make heavy use of these protocols.

In the late 1980s, as graphical, window-oriented user interfaces became popular, protocols were developed to allow remote windowing operations, much as earlier protocols allowed remote terminal operations. Although conceptually similar, the operation of such windowing protocols is markedly different.

Let's say we are preparing a huge PowerPoint presentation for a meeting on Friday. All of the PowerPoint files and PDFs and images that you want to use in your presentation are saved on the hard drive of your work computer.Thursday rolls around and you wake up with a nasty stomach virus.You don't feel well enough to go to the office, but you need to finish that presentation. Here's where remote login can help.

In simple words Remote Login means to access other computers on the network or on the other network by the use of telnet or rlogin command.In other words we can also say that Remote Login means to access native computer from the other computer on the network when you are connected to the internet.

Remote login, however, uses simple desktop sharing software to give you a "remote control" for accessing your computer and all of its software and hard drive files from any Internet-connected device anywhere in the world.

Remote login will only work if the host computer is powered on, connected to the Internet and running the desktop sharing software

Common tools used are:Telnet,SSH(secure shell),Putty,etc

group19_angels : http proxy server

A proxy server is one that receives requests intended for another server and that acts on the behalf of the client (as the client proxy) to obtain the requested service.Basically it acts as an intermediate between the client and the server. A proxy server is often used when the client and the server are incompatible for direct connection. It may also be used for screening purposes i.e for filtering purposes ,to enable the administrator to control access to undesirable sites. The proxy server may also be used for caching purposes which enables faster access to frequently used websites.

We will host a proxy server both in Linux/Windows and for the demonstration purpose, we will host a proxy server in our home router and computer, configure a dynamic DNS (through dyndns.org) to connect to it.

Our tool of choice is Squid: