subnet scanner

principle is very simple, using the ARP protocol to broadcast their own IP address to the network, if the response there is an IP conflict, this function in the tcp/ The first volume of the IP protocol ARP protocol chapter is described in detail. This first uses the ping command to probe the set IP address, and then in the ARP cache to find out if there are valid records, if any, there is an IP conflict. There is no need to care whether the ping command succeeds, whether or not it succeeds, as

protocol, all the "0" Network numbers are interpreted as "local" networks.* Return addressClass A network address 127 is a reserved address for network software testing and communication between local processes. It is called loopback address ). No matter what program, once data is sent using the return address, the protocol software returns immediately without any network transmission.According to TCP/IP protocol, 1. Groups with network numbers 127 cannot appear on any network. 2. The host and

Well! The late stage of procrastination, has been incurable, survived the night of two nights, the basic computer network curriculum design of the Web scanner function realized.In fact, write a scanner is also very fun, involving the raw socket programming, can indulge in DIY packets (of course, do not conform to the rules of the packet, such as checksum errors can not be the way), harvest quite deep. Among

Turn from: http://hi.baidu.com/ww2000e/item/98f7b9f6d396d5b430c1994f First of all, we look at a CCNA test common problem: The IP address of a host is 202.112.14.137, the mask is 255.255.255.224, requires computing the network address and broadcast address of the host network. 255.255.255.224 masks contain 256-224 = 32 IP addresses (including network address and broadcast address), the network address with this mask must be a multiple of 32. And the network address is the beginning of the

IP addresses are classified into five categories--------------------------------------------------------------------------------------------------------------- ----------------------------------------------------the meaning of the subnet mask and subnetting according to the subnet maskThe subnet mask is used to divide subnets. For example, a Class A network can h

First, what is a subnetThe IP address consists of two parts, the network ID and the host ID. The network number identifies a subnet on the internet, and the host number identifies a host in the subnet. A subnet is a smaller network that is based on a particular type of address.Second, why to divide the subnetThe Internet organization defines five IP addresses, wi

Summary: Class A, B, C is actually the concept of address block, the so-called application of a class C address, refers to the application of a Class C address block. C class Address block of specific IP address of this class C address block, of course, also belong to Class C address classes. A subnet mask is a subnet, such as a number of 200多万个 address blocks that divide the entire IP address into Class A,

Topic: Solution for subnet mask faults of switches: Fault Phenomenon: Asymmetric Network Access failure, troubleshooting: Firewall and telecommunications? Subnet Mask. Fault Summary: Why can't I access the Internet but cannot connect to the headquarters? fault tips: the important role of subnet mask. Network connectivity is a common phenomenon. I believe many peo

Transferred from: http://baike.baidu.com/view/65511.htm Http://baike.baidu.com/view/878.htm The IP address is the network number and host number to represent the host on the network, only in a network number under the computer can be "direct" interoperability, different network number of the computer through the gateway to exchange. But such a division does not seem very flexible in some cases. For this reason, the IP network is also allowed to be partitioned into smaller networks called subnet

Understand these pointsL How many subnets will be generated by the subnet mask you select2 x -2 (x represents the number of bits of the network bit borrowing host, that is, 2 into 1 parts, now the network is no longer required-2, can be used all, but need to add the corresponding configuration commands,L How many hosts each subnet can have2 of the Y-square -2 (Y for the host bit, that is, 2 in 0 parts)L a v

It is the preferred Enterprise network security scheme for many network engineers to divide the enterprise's local area network and improve the security of the network through the rational subnet division. Indeed, with the help of the subnet mask, the enterprise network can be divided into several relatively independent networks. The company's confidential department is then placed in a separate

the limited broadcast address ). * "0" Address According to the TCP/IP protocol, all the "0" Network numbers are interpreted as "local" networks. * Return address Class A network address 127 is a reserved address for network software testing and communication between local processes. It is called loopback address ). WhateverProgramOnce data is sent using the return address, the protocol software returns immediately without any network Transmission. According to TCP/IP protocol, 1. Gr