reset tcp ip stack

, because the IP packet identification field will not be infinitely long, according to IPV4. It seems that the upper limit should be 4G (64k*64k).Rely on such a mechanism. There is no "package length" field in the TCP header. and rely entirely on the IP layer to process the sub-frame. This is why TCP is often referred

Finally, we finally came to the large header TCP protocol. In order to provide reliable transmission services for the application layer, various mechanisms are designed for tcp to achieve possible errors during transmission, such as packet loss, retransmission, disordered order, and link transmission errors. 1. TCP Overview First, let's take a look at the header

application for processing. After the destination host receives the packet, how to reach the application at the end of each layer protocol stack. The entire process is shown in the following illustration. The Ethernet driver (NIC) first determines the payload of the data frame according to the "Upper layer protocol" field in the Ethernet header (payload, which means removing the actual data transmitted outside the protocol header), is the datagram

package, and on their own side of the force to switch off the connection; Both of these methods can achieve the effect of the reset attack. It seems scary, but the key is how C can forge a packet to B? Here are two key factors, source port and serial number.A TCP connection is a four-tuple that uniquely identifies a connection by the source ip+ source port,

option field. reserved : 6-bit, reserved for future use, currently 0. control bit : A total of 6 control bits, indicating the nature of this paper, meaning as follows:URG emergency : When Urg=1, it tells the system that there are urgent data in this message, priority transmission (such as emergency shutdown), which should be used in conjunction with the emergency pointer field.ack Acknowledgement : The confirmation number field is valid only when ack=1. After a

TCP/IP RoamingTCP/IP is the foundation of the Internet Protocol stack, which includes dozens of large and small protocols. This article is mainly related to HTTP, TCP, IP protocol. We often learn that the network model is seven or

TCP Learning Record (from TCP/IP Volume 1) tcp's TIME_WAIT status TCP requirements, first issue the FIN end, after both parties completely close the connection, the maximum message segment survival time (MSL) remains in the TIME_WAIT status until two times ). The recommended MSL value is 120 seconds, that is, it takes

1. OverviewTCP provides a connection-oriented, reliable byte-stream service. Full-duplex communication. A TCP connection is uniquely determined by a 4-tuple: Local IP address, local port number, remote IP address, and remote port number.TCP packs the user data into a message segment, initiates a timer when it sends the data, confirms the received data on the othe

Function call relationships in the tcp protocol stack during tcp three-way handshake in the Linux kernel-Linux general technology-Linux programming and kernel information. For more information, see the following. Recently, I need to modify a set of tcp protocol stacks. I simply looked at the function calling process of

and slice The first digit is not used. Every two DF (don't fragment) bits are 1. If the transmitted datagram exceeds the maximum transmission unit, the datagram is discarded, and sends an ICMP error message. The third-digit MF (more fragment) indicates whether more slices exist. The value of this parameter is 1, indicating that more fragments exist in the future. The last mf is 0.After an IP packet is split, each datagram has its own header, but the

normal circumstances Header Length (4 digits) Because the options are not long, you need to identify the length of the entire header field (unit: 32 characters), that is, the number of 5 + options. 4-bit. The unit is 32 characters. Therefore, the maximum length of the header is 15*4 = 60 bytes, that is, the maximum length of the option is 40 bytes (10 options ). Flag URG Indicates that the upper layer entity of the sender is marked as "urgent" data in the message segment. When URG = 1, the foll

Baidu homepage as an example. First, use the DNS protocol to resolve the URL to an IP address, then establish a TCP connection between the client and the server, and use Wireshark to capture the group, for example: Figure 4 establish a TCP connection group by Wireshark capture You may think it is a bit strange. In theory, it should be three groups. How can we h

In the Connection Properties dialog box for Windows Server 2003 (Windows 2003), if you click the Internet Protocol (TCP/IP) option, the Uninstall button is dimmed and is not available. This is because the TCP/IP protocol is the core component of Windows Server 2003 and cannot be deleted. What if we need to

received data needs to be passed to the upper application protocol immediately. PSH is 0 o'clock, it does not need to be transmitted immediately but first cached.RST Reset Flag?A bit of 1 indicates that an exception in the TCP connection must be forced to disconnect.?SYN Synchronize flag?Used to establish a connection. A SYN of 1 indicates that you want to establish a connection and set the initial value o

1.TCP of servicesin a TCP connection, only two parties communicate with each other. TCP provides reliability in the following ways:1) The application data is segmented into the data block that TCP considers most suitable for sending. This is completely different from UDP, where the application-generated datagram lengt

intercept a TCP connection is still very difficult, you need to know the source IP, source port number, but also know the serial number, and this initial sequence number is random, and then the serial number of the packet with this side of the data transferred how much has a relationship. And why the firewall to disturb the serial number, because this serial number in the operating system seems to have a c

protocol stack meet expectations. The process of the TCP protocol stack is only two ends, one end uses the system call to simulate the stack behavior, the other end is the package we construct. Common scenarios are mainly: Server scenarios, client scenarios. Server scenario: The server scenario uses system calls (that

TCP/IP protocolDanbo 2015-7-2This article for reference TCP/IP detailed volume one, some knowledge points added to the author's own understanding, if there are errors, please correct me, you can contact me Weibo!The TCP packet format and

TCP/IP OverviewTCP/IP is generally considered to be a four-layer protocol: Link layer. Also known as the data Link layer or network interface layer, including device drivers and network interface cards, which work together with the physical interface details of the cable. Network layer. Handles the grouping of activities in the network, such as the r

. PreprocessingThis section describes the TCP message segments received for preprocessing. The approximate flow of processing is as follows:1. Obtain the IP and TCP headers from the first mbuf.2. Verify the test and the TCP.3. Verify the TCP offset field.4. Place the