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What is IP Spoofing and how to avoid it?

IP Spoofing is a technique used to gain unauthorized access to machines, whereby an attacker illicitly impersonates another machine by manipulating IP packets. IP Spoofing involves modifying the packet header with a forged (spoofed) source IP address, a checksum, and the order value. Internet is a packet switched network, which causes the packets leaving one machine may be arriving at the destination machine in different order. The receiving machine resembles the message based on the order value embedded in the IP header. IP spoofing involves solving the algorithm that is used to select the order sent values, and to modify them correctly.

MS-DOS Ipconfig Command Reference

Ipconfig is a MS-DOS command-line tool used to display and manage the network settings of your computer. Ipconfig is available on Windows machines, and it displays the current network connection details and DHCP client settings.

What is a proxy server?

A Proxy server is a computer that sits between a client computer and the Internet and provides indirect network services to a client. A proxy server intercepts all client requests and provides responses from its cache or forwards the request to the real server.


What is DHCP?

The Dynamic Host Configuration Protocol (DHCP) is a network protocol that functions at the application layer of the Internet Protocol (IP) suite. A server that uses DHCP will be able to dynamically assign IP Addresses and other network configuration parameters to devices on the network; thus, allowing communication to a second network. The protocol can be implemented in networks of any size, ranging from small home area networks (HANs) to large campus area networks (CANs) and even the networks used by Internet Service Providers (ISPs).

What is a TCP/IP?

TCP/IP, Transmission Control Protocol/Internet Protocol, is the suite of two protocols, TCP and IP, used to interconnect network devices on the Internet. The TCP performs the handshake between the network devices to establish a socket. The socket remains open during the communication. The source TCP converts the data into packets and sends them to the destination TCP. The TCP performs acknowledgment for the successful delivery of the packets. If a packet drops on the way, the source TCP resends the packet. The IP layer is responsible for sending and receiving the data to the correct destination. The TCP/IP stack is comprised of the following layers.

What is a MAC Address?

MAC, Media Access Control, address is a globally unique identifier assigned to network devices, and therefore it is often referred to as hardware or physical address. MAC addresses are 6-byte (48-bits) in length, and are written in MM:MM:MM:SS:SS:SS format. The first 3-bytes are the ID number of the manufacturer, which is assigned by an Internet standards body. The second 3-bytes are serial numbers assigned by the manufacturer.


What is a Subnet Mask?

address and the host address. A subnet mask separates the IP address into the network and host addresses (<network><host>). Subnetting further divides the host part of an IP address into a subnet and host address (<network><subnet><host>) if additional subnetwork is needed. Use the Subnet Calculator to retrieve subnetwork information from the IP address and Subnet Mask. It is called a subnet mask because it is used to identify the network address of an IP address by performing a bitwise AND operation on the netmask.

What is an IP Address?

The Internet Protocol Address (or IP Address) is a unique address that computing devices such as personal computers, tablets, and smartphones use to identify themselves and communicate with other devices in the IP network. Any device connected to the IP network must have a unique IP address within the network.

Email Delivery Problems Explained

With ever growing number of spam emails flooding the Internet, more and more ISPs tighten their email filtering system to prevent spams delivered to their clients. It is virtually impossible to block even 50% of the spams arriving in a mail server, and there will always be false positives (legitimate emails filtered as spams). In an effort to reduce spam emails, the Federal Trade Commision (FTC) passed the CAN-SPAM Act of 2003, but the Internet spam traffic is still on the rise.