ip packet sniffer

isolation (The following example will see this).Third, the case analysis3.1 OverviewOr to visit Baidu home page For example, first use the DNS protocol to resolve the URL to an IP address, and then between the client and the server to establish a TCP connection, with Wireshark capture groups such as:Figure 4 Wireshark capture establishing a TCP connection groupingYou will find it strange, in theory it should be 3 groups, how to have 6 groups? First o

let's start by understanding the following basic concepts : 1. Forwarding: Represents the process of selecting a path for a group 2, IP Forwarding: Its traditional method is IP routing (IP routing), IP forwarding it is to send the datagram to select the path. 3, Group: (most computer networks can not continuously trans

let's start by understanding the following basic concepts :1. Forwarding: represents the process of selecting a path for a group2,IP forwarding: Its traditional method is IP routing (IP routing), IP forwarding it is to send the datagram to select the path.3, Group:(most computer networks can not continuously transmit a

IP packet header information format: + ------------------------------------------------- + | Version (4 digits) | + ------------------------------------------------- + | Header length (4 digits) | + ------------------------------------------------- + | Eight-bit service type (ToS) | + ------------------------------------------------- + | Total Packet Length (16 b

The following TCP/IP data packets are the data packet structures that I have used during socket and wipcap network programming. These data packets seem inconspicuous at ordinary times, it will be very useful when actually used ....../* Physical Frame header structure */Typedef struct {?? Byte? Desmac [6]; // target MAC address?? Byte? Srcmac [6]; // source MAC address?? Ushort? Ethertype; // Frame Type} Dlc

I. packet header in TCP/IP protocol In TCP/IP networks, the underlying protocol is the same thing, and the application layer protocol is the same thing. Therefore, as an application layer protocol, HTTP can transmit much content and how to transmit it (for exampleGenerally, an HTTP packet consists of 48 KB. When the

Author: David Zhou Mail: leaf_zhou_8@hotmail.com Time: 2006/01/19 IP packet header information format:+ ------------------------------------------------- +| Version (4 digits) |+ ------------------------------------------------- +| Header length (4 digits) |+ ------------------------------------------------- +| Eight-bit service type (ToS) |+ ------------------------------------------------- +| Total

I. Hierarchy of TCP/IP protocol clusters:II. Specific protocols include:Note: 1. ARP and RARP are used for switching between physical addresses and network addresses. They should belong to the physical link layer. However, since ARP and RARP both have their own frame types in Ethernet frames, they are drawn between Ethernet drivers and IP addresses. 2. ICMP and IGMP are usually used to query network managem

1. TCP/IP layered model Of course, here we will only discuss the important layer-4 01. Application Layer (Application Layer): the Application layer is a broad concept. It has some similar system-level TCP/IP applications and Application protocols, as well as many enterprise applications and Internet applications. The http protocol runs at the application layer. 02. Transport Layer (Tanspot): the transport l

I. IP address data packet structure: The fields are described as follows: 1, version: version number, 4 bits, indicates the version of the IP protocol. 2, header length: header length, 4 bits, unit: 4 bytes, so the maximum length is 4*(2 ^ 4-1) = 60 bytes, the first fixed part is 20 bytes in length, and the variable part is 0 ~ 40 bytes. 3, differentiated serv

IP data packets can be in either IPv4 or IPv6 format. IPv6 is an improved version used to replace the IPv4 protocol in the future. For the purpose of this article, we can ignore the difference between the two for the moment. We only use IPv4 as an example. The following is an IPv4 packet in the IPv4 format. We fold the entire sequence according to 4 bytes to better display the frame. The

Brief introduction With the addition of Windows Firewall to MICROSOFT®WINDOWS®XP Service Pack 2 and Windows server™2003 Service Pack 1, and Internet Protocol security (IPSEC) in public Division Intranet, Information Technology (IT) professionals need to understand the specific ways in which TCP/IP protocols and related components in Windows handle unicast Internet Protocol (IP) packets. The detailed knowle

To learn the TCP/IP protocol, you must learn how to analyze data packets. The following is a simple example to describe how to analyze an IP data packet. 1. Ethernet (RFC 894) frame format The source address and destination address are the hardware address (also called the MAC address) of the network card. The length is 48 bits and is fixed at the factory of

The service provided by the network layer is the forwarding of packets between different network segments.IP packet Structure1, Format (4byte*5 per line)2, Version V4 V63, Header length 20 (fixed) + variable length? , Differentiated ServicesWin2008 start: Gpedit.msc set DSCP value5, total lengthSet the meaning of the head length: Because the IP header has a mutable part. Head length measurement head length,

For the sake of pseudo IP, we specially made an IP package and used C # to rewrite the IP header checksum algorithm. Document 1: IP Header Format: Version Number (4 digits) IP header length (4 digits) Service type (8 bits) Packet

ICMP is considered a part of the IP layer, which transmits error messages and other information that requires attention. ICMP packets are often used by the IP layer or higher protocol (TCP/UDP) (some error messages are returned to the user process ). ICMP packets are transmitted inside IP datagram. For example, the format of ICMP packets is as follows: for variou

Explanation of TCP/UDP data packets (1): IP data packet structure 1. Graph IP data packets consist of four bytes per line (32 bits) from the header and Data) the first part contains at least 20 bytes (5 rows), and the option part is optional. [length of the option to be supplemented] 2. The first part is fixed. 1. The first line is the

Tag: Option packet double quotation mark host NetworkWireshark capturing packets that have been specified by IPCapturing the filter capture before it is set in Capture option, capturing only eligible packages, can avoid generating large capture files and memory footprint, but does not fully replicate the network environment when testing.Host 192.168.0.1//Fetch all packets received and sent by 192.168.0.1SRC host 192.168.0.1//source address, all packet

Prior to groping the computer, know that the HP compaq6910p has remote wake-up function. At that time did not care, now suddenly have the actual demand, just remembered to toss a bit. Look at the online approach, mainly two aspects of Setup, BIOS and NIC. After that can use magic packet to the packet wake, but the use of the software on the Internet is only required to fill in destination Ethernet Address,

Have you ever wondered how to prohibit others from accessing Web server, POP3, FTP, and so on in the lan. So how can we disable it? As we all know, TCP is connection-oriented, and the connection can be confirmed successfully only after three handshakes are made during the connection. Then we should be able to forge a response from the provider after the first handshake, so that the TCP connection fails and a port cannot be accessed. The procedure is as follows: Void decodeip (BUF, ibufsize) //