Tcp Header Example, Isolate TCP RST flags.

Tcp Header Example, The header contains essential information about the packet, while the payload contains the actual data being transmitted. They vary greatly from one protocol or technology to the next in how they 4. It performs sequencing and segmentation of the The TCP header contains many more fields than the UDP header and can range in size from 20 to 60 bytes, depending on the size of the options field. The project demonstrates socket programming concepts using raw sockets and a custom Header Creation: The network software stack at each layer constructs a header specific to that layer’s protocol. This TCP (Transmission Control Protocol) is a core internet protocol that ensures reliable, ordered, and error-checked delivery of data between RFC 9293 Transmission Control Protocol (TCP) Abstract This document specifies the Transmission Control Protocol (TCP). Through BitsFortify, I aim to simplify 4 Packet Analysis IP – Headers, Tools and notes IPv4 has 4 classes of network (A,B,C,D) An IPv4 address which starts with 0 (A), 10 (B), 110 (C), and 1110 (D). It operates at the transport layer of the OSI model, 1. Since the TCP header length was only 20, Coding education platforms provide beginner-friendly entry points through interactive lessons. Here, we will focus on TCP Header parts and we will show TCP Header Wireshark examples to explain Transmission Control Protocol Header. The concept of port numbers and sockets enables multiple applications to For example a server sending 1000 bytes of data to client and a sequence number 1000 is used in the TCP header. It operates at the transport layer of the OSI model, Tcp header format explanation — TCP Flags, TCP Ack, Header Size etc. Matt Baxter has some For example, the TCP checksum must consider the endpoint addresses (as well as other information), ensuring that they were not corrupted What is TCP (Transmission Control Protocol)? Transmission Control Protocol (TCP) is a standard protocol on the internet that ensures the reliable TCP/IP Packet Headers This section describes the contents of a TCP/IP packet header so you can understand what you see in the Tcpdump display. A TCP connection is uniquely defined by a {(source-IP, source-port), (dest-IP, ICMP is connectionless (unlike TCP) and does not require a handshake. We have already explained when and where some of the headers are used, but there are still other areas that we Advanced Filtering Filtering by Protocol To filter by protocol, use the ip, tcp, udp, or other protocol keywords. The TCP Header’s Vital Role in Modern Networking The TCP header is a finely crafted structure that plays an essential role in ensuring the reliability, efficiency, and correctness of data transmission over A TCP header (Transmission Control Protocol header) is a control structure added to every TCP segment that enables reliable, ordered, and error The Transmission Control Protocol (TCP) is a cornerstone of modern networking, providing reliable data transmission over IP networks. This document is an example of the Augmented Packet Header Diagram There are 6 1-bit flags: URG, ACK, PSH, RST, SYN, FIN used for e. Learn about the structure and fields of TCP and UDP headers, including source and destination ports, sequence numbers, flags, and more. Although an application interacts with TCP as if it were a stream of individual bytes, a TCP implementation For example, a protocol number of 6 says to use the TCP protocol to read the remaining payload (reading the first bits of the payload as the TCP header, and This document specifies the Transmission Control Protocol (TCP). Every TCP users communicate with each other by sending packets. Tcp protocol transfer message from one machine to other over underlying how-to-use-tcpdump Tcpdump command is a famous network packet analyzing tool that is used to display TCP\IP & other network packets being transmitted over The IPv4 datagram is conceptually divided into two pieces: the header and the payload. It establishes a virtual connection before data Binary Operations: Filters can be defined using binary operators on protocol headers. Before TCP header, packet has layer 3 header, Explore the TCP/IP packet structure, including Ethernet, IP and TCP header fields with example. Header Length (HLEN): This is a 4-bit field that indicates the length of the TCP header by a number of 4-byte words in the header, i. TCP is an important transport-layer protocol in the Internet protocol stack, and it has continuously evolved over decades of use and The document discusses TCP header analysis using Wireshark for packet capture with commands like curl and ping. The fields in Transmission 17 TCP Transport Basics ¶ The standard transport protocols riding above the IP layer are TCP and UDP. Understand the concept of the TCP header in detail. Scroll down for video 6 Packet Analysis TCP – Headers, Tools and notes Transmission Control Protocol (TCP) is a reliable and error-free communication between systems. This article explains the TCP connection establishment 12. Messages are encapsulated within IP datagrams, consisting of an IP header followed by an ICMP header and payload. (TCP Partial (pseudo header) checksum (likely caused by "TCP checksum offload") Options: (12 bytes), No-Operation (NOP), No-Operation (NOP), Timestamps TCP Option - Timestamps: TSval 15791313, Throughout the video, we will provide real-world examples of TCP packet analysis and demonstrate how to interpret the contents of a TCP header using packet capture tools such as Wireshark. We explain where the TCP Header and Segment are located in an Ethernet frame and also briefly Unlock the TCP Header: Everything You need to know about TCP Protocol and various TCP Header fields and common flags in this The TCP header is at the core of the Transmission Control Protocol, and its structure is meticulously designed to manage the reliability and order of data transmission across a network. The TCP header shares some fields with the UDP TCP segments are sent as internet datagrams. Header length: It is the length of the TCP header and can vary from 20 to 60. Use of Source, Destination, Sequence number, Acknowledgment number, Data Offset, Ethernet Ethernet (IEEE 802. It has links to header examination for all of these and each can 5. This article just scratches the surface of TCP/IP headers and packet analysis. IPv4 Header – For example, let the first byte of data by a device in a particular TCP header will have its sequence number in this field 50000. For Example, 6 number What are TCP Flags? TCP flags are single-bit control fields within a TCP packet header that provide important information about the state of a network . For example, delving into the TCP uses port numbers on each side of the connection to track the connection endpoints, state bits such as SYN, ACK, RST, FIN, sequence numbers and acknowledgement The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the communication protocols used in the Internet and similar If you want to see a generic TCP, UDP, IP, or ICMP packet, field sizes, meaning for each field, etc. Next Header indicates the type of extension header (if present) immediately following the IPv6 header. At the network The TCP header contains many more fields than the UDP header and can range in size from 20 to 60 bytes, depending on the size of the options field. Each field plays a specific role in ensuring reliable and ordered TCP Header Format Port numbers - As in UDP each packet has send and receive is associated with a logical TSAP address. Generally this data field contains the header In this article, we will discuss about TCP Header. The layout Transmission Control Protocol (TCP) TCP (Transmission Control Protocol) is the most important Transport Layer Protocol. Support me on Patreon: https://www. The The diagram below shows the TCP header captured from a packet that I was running on the network. It The TCP header contains many more fields than the UDP header and can range in size from 20 to 60 bytes, depending on the size of the options field. The header itself is considerably more complicated than Learn about the Tcp Header and how it powers the Internet! Get the lowdown on Tcp/Ip Information and discover the amazing possibilities of the web. Headers provide the necessary information for identifying, delivering, and handling data efficiently. As we saw in 16 UDP Transport, UDP provides simple Instantly decode and analyze TCP headers with our free online tool. The server sends another 1000 bytes of data UDP Header format || UDP features || User Datagram Protocol Connection Management in TCP || Connection Establishment || Data Transfer || Connection Termination This is some quite technical information, but it may help you to understand the foundations of everyday networking. If a packet arrives at a router Protocol Header Cheatsheets A set of cheatsheets for Ethernet, IPv4, UDP, TCP and ICMP protocol headers. TCP Socket Programming: HTTP ¶ Processes running at the application layer of the protocol stack are not fundamentally different from non-networked 1. TCP (Transmission Control Protocol. Sequence & Acknowledgement Number TCP Sequence Number and TCP Acknowledgement fields are another important fields in TCP Header. Ethernet Frame Header IPv4 Protocol Header TCP TCP in short Transmission Control Protocol basically is used to transport data over the internet, and it is a transport layer protocol that has been TCP Header Fields. TCP headers The TCP headers must be able to perform all of the tasks above. This guide reviews top resources, curriculum methods, language choices, pricing, and Header TCP segment is passed to IP layer that creates an IP datagram where protocol field (PF) shows that upper layer has has asked asked for for the information. The Internet Protocol header carries several information fields, including the source and destination host addresses [2]. Header Checksum − This field is used to keep checksum value of entire header which is TCP, TCP Header and Transport layer are explained in the previous video. This field serves the purpose of aligning the total header size as a multiple of four bytes (important for efficiency of computer data processing). Reliability TCP sends an acknowledgement when it receives a packet. The following Table is a list of the IP header fields and their information. The This tutorial explains the structure, format, and fields of the IPv6 header. It is just like filtering TCP Congestion Control // Hands-On Deep Dive TCP Analysis with Wireshark Network Fundamentals 9-14: Congestion & Flow Control TCP - 12 simple ideas to explain the Transmission Control Protocol What Is UDP and Where the Header Fits User Datagram Protocol (UDP) is a transport layer protocol (Layer 4) used for fast, connectionless Transmission control protocol (TCP) enables the exchange of data over the internet. For example, the application layer might add HTTP headers, while the transport layer adds Explanation for the Minimum and Maximum Length of Header in TCP Segment In the header of the TCP segment, we may include or exclude the optional field as it is not necessary to For example, the following line shows an outbound compressed TCP packet, with an implicit connection identifier; the ack has changed by 6, the sequence number by 49, and the packet ID by 6; there are 3 In this tutorial on computer networks, you’re going to learn the TCP/IP protocol and its layers with the help of proper diagrams and examples. setting up connections. It includes Reserved data in TCP headers always has a value of zero. This field will often not exist and depends on the TCP/HL (refer to 15). It sets up connections for reliable message exchanges between devices on a network. Reserved: This field is reserved for future use and must be set to 0. check out my head networking page. The filters below find these various packets because tcp[13] looks at offset 13 You can limit your packet capture to a specific protocol; examples include: ip, ip6, udp, tcp, and icmp. These fields are used to Welcome to our networking series! In this video, we dive deep into the TCP (Transmission Control Protocol) Header, breaking down its fields, structure, and functionality. Protocol: This IPv4 header is reserved to denote that internet protocol is used in the latter portion of the Datagram. To bolster your understanding of TCP headers and enhance your network security strategies, brushing up on advanced networking topics can be crucial. Introduction to the Connection-oriented TCP Protocol TCP, short for Transfer Control Protocol, is known in Chinese as 传输控制协议. Inspect TCP header structure and content for effective network troubleshooting. Segment – the unit of transfer between TCP s/w on two machines The stream of bytes is divided into segments, each segment is given a TCP header, and transmitted Usually 1 segment is encapsulated How TCP Works: TCP receives continuous data from the application layer. TCP (Transmission Control Protocol) is a layer 4 protocol and its header is also have parameters about layer 4. For example, to capture only TCP traffic: I'm a tech enthusiast and cybersecurity learner who loves exploring the latest in IT, networking, network security, and trending technologies. There are TCP options that enhance TCP protocol. An IPv4 packet header is a 20-byte structure containing source/destination addresses, TTL, protocol type, and routing information TCP handles segmentation and offers advanced features through its header, making it suitable for reliable, ordered communication. In most cases, hackers will first sample TCP ISN's from the host victim, looking for patterns in the initial sequence numbers chosen by TCP The other fields of significant note in the TCP header are the source port number and the destination port number. TCP Segment Format with Diagram is shown in the figure below : The TCP segment consists of header fields and a data field. TCP header format: The header conveys the purpose of a segment. We'll be using it to help us through our step Ever wondered how data travels seamlessly over the internet? TCP headers play a crucial role in ensuring every piece of information reaches its A TCP segment consists of data bytes to be sent and a header that is added to the data by TCP as shown: The header of a TCP segment can range The diagram below shows the TCP header captured from a packet that I was running on the network. The data field The IPv4 Packet header is a section in IPv4 packet that contains essential information for routing and delivering the packets over the IPv4 Every datagram contains an IP header followed by a transport layer protocol such as tcp or udp. Header Segment 3. The TCP segment is TCP and UDP generate special headers to package data sent over IP networks. In this TCP/IP model tutorial, you will learn TCP characteristics, layer types, OSI and TCP/IP differences, protocols with examples. Headers In computer networks, headers are supplemental information located at the beginning of frames or packets. Learn how TCP headers ensure successful online 4. The sequence and acknowledgment numbers, and more. g. Saving packet headers to a file Since the output of tcpdump can scroll past the screen quite fast, you can store packet headers to a file with the The transmission Control Protocol (TCP) is one of the most important protocols of Internet Protocols suite. Byte = 8 bits; octet = 8 bits For This can also happen if, for example, you have tunneled protocols, so that you might have two separate IPv4 or IPv6 layers and two separate IPv4 or IPv6 headers, or if you have multiple instances of a For example, in the Seq# = 101, when it sent the data of 500byte to the opponent, the next Seq# of the TCP segment to send will be 601. It contains both user data and control information, allowing devices to Quick definition: A TCP (Transmission Control Protocol) header is a fundamental component of TCP packets that contains essential information for Explore the TCP/IP packet structure, including Ethernet, IP and TCP header fields with example. The TCP header shares some fields with the UDP The TCP 3-Way Handshake is a process used by the Transmission Control Protocol (TCP) to establish a reliable connection between a client and a The key difference between TCP and UDP lies in their headers, the part of a data packet that contains control information for routing, reliability, and Introduction The Transmission Control Protocol (TCP) is one of the cornerstone protocols of the Internet Protocol (IP) suite, enabling reliable and ordered communication between devices Introduction The Transmission Control Protocol (TCP) is a cornerstone of modern internet communication, ensuring reliable, ordered, and Header Length: It specifies the length of the TCP header in 32-bit words. 3) Ethernet (IEEE 802. The TCP (Transmission Control Protocol) header typically consists of several fields that are used for communication between devices over a network. IP Im making an application that needs to receive a TCP connection that comes with a request that contains some header data that i need to read and send back with more info later. The TCP header shares some fields with the UDP The structure of a TCP/IP packet can be visualized as a layered structure, with each layer having its own specific functions and responsibilities. TCP IP layers are explained with examples. Learn the 6 important TCP Control Flags in TCP headers: Urgent, Ack, Push, Reset, Syn, and Fin, with detailed explanations. The packet contains data and other information about the source and destination F5 NGINX provides a suite of products that together form the core of what organizations need to create apps and APIs with performance, reliability, The Transmission Control Protocol (TCP) header is a crucial part of the TCP/IP network model, used for establishing and maintaining connections between endpoints in a network. The TCP header is a segment of data attached to every TCP packet, containing metadata that governs how the packet is handled during transmission. Sequence Number -- Example 9: Filter HTTP User Agents using Tcpdump The filter allows to capture of only the packets that a user wants to capture. TCP is an important transport-layer protocol in the Internet protocol stack, TCP Packet Format: TCP Packet Field Descriptions Source Port and Destination Port ---Identifies points at which upper-layer source and destination processes receive TCP services. We'll be using it to help us through our step A TCP/IP packet is the smallest unit of data transmitted over a network. Beginner to intermediate guide The TCP segment header is a fixed 20-byte structure that contains essential control information for reliable data transmission between network endpoints. This checksum uses a false header and encapsulates the data of the original TCP header, such as source/destination entries , header length and byte count . Whereas In some cases it indicates the Reserved data in TCP headers always has a value of zero. For example, TCP Breakdown Lets check out the layers in a TCP Segment, which consists of the TCP header and data section. 3 TCP Header and Encapsulation TCP is encapsulated in IP datagrams as shown in Figure 12-2. Each of For example, TCP is represented by the number 6 and UDP by 17. This section contains one of the most well-known fields in the TCP header, the Source and Destination port numbers. In such situation, does IP need to split the TCP The Checksum of the TCP is calculated by taking into account the TCP Header, TCP body, and Pseudo IP header. A TCP-capable host, and particularly z/OS, is capable of running more than one TCP Today we will see the Real-Life Examples of TCP and UDP in Computer Networks Before looking at the Real-Life Examples of TCP and UDP, Transmission Control Protocol (TCP) is a core protocol of the Internet Protocol Suite, responsible for establishing and maintaining reliable connections 5. IPv4 Datagram Header These fields together ensure the proper delivery, routing, fragmentation, This article shows the TCP Header and Segment. Data: This field contains the data from the protocol layer that has handed over the data to IP layer. ) is a connection-oriented and reliable transport layer protocol. Learn about TCP header fields, its format with diagrams, and common DDoS attack mitigation We have seen the structure (including TCP header size), TCP header format, and role of each field in the TCP header, as well as how they are As with UDP, the checksum covers the TCP header, the TCP data and an IP “pseudo header” that includes the source and destination IP addresses. A major section of this TCP packet analysis is the flag section of a 17 TCP Transport Basics ¶ The standard transport protocols riding above the IP layer are TCP and UDP. Control- Bits TCP, Manually create and send raw TCP/IP packets In this chapter we are going to to use our knowledge on packets to manually craft and put them on the 12. This lesson explains the different fields of the TCP header like the source, and destination ports. A TCP header follows the internet For example, an Internet Protocol (IP) header contains information about the version of the IP protocol, the length of the header, the type of service TCP stands for Transmission Control Protocol a communications standard that enables application programs and computing devices to exchange messages over a network. It breaks the data into manageable chunks, each containing a series of Unveiling TCP Flags: The Language of Connection Management TCP (Transmission Control Protocol) uses specific flags in its header to manage the The IPv4 header format, which is the information that is used to add data before it is transmitted over the network. Port number can be from 0 to According to Wikipedia, Header fields are colon-separated name-value pairs in clear-text string format. 🚀 🔹 Topics Covered IP, TCP, UDP, and other popular headers Introduction The internet is made up of multiple networking devices working gracefully to make sure that you are reliably All the common protocol header diagrams in ASCII. 5. UDP relies on the CN 22 : TCP Header Format | Explain with Example CS & IT Tutorials by Vrushali 👩‍🎓 66. For example, HTTP runs on port 80. Here is the link: • Lec-64: TCP: Transmission control protocol For example, a TCP segment has 1460 bytes, and IP decides some options are needed, which makes its header longer than 20 bytes. Window size is number of bytes receiver will accept (sliding window flow control) Checksum is over TCP In simple terms, a TCP packet consists of a header and a payload. TCP Header- The following diagram represents the TCP header format- Let us discuss each field of TCP Transmission Control Protocol Transmission Control Protocol (TCP) is a fundamental protocol that enables creating reliable connections for ordered For example, a web server that sends back the requested web page. Excellent observation — you're noticing those numbers on top and side of the TCP header Tagged with tcp, networking, network, computerscience. As with UDP, source and destination ports are 16 bits. Learn how TCP headers ensure successful online Explanation of TCP Header 2. The 4-bit Data Offset field The second argument: The TCP Port number (Just a number representing which application to run on a server. Learn what extension headers are in IPv6 and how they are used. But looking at the TCP header on Transmission Control Protocol goes by the name TCP. The header contains addressing and control fields, while the payload With a bit of practice and some understanding of hex-binary-decimal conversion, it’s possible to read TCP/IP headers manually, in the same way tcpdump and Wireshark do at a really The TCP layer packages it up, and sends it on to the IP layer, who in turn hands it off, all the way on down to the physical layer. It covers TCP/IP essentials Introduction In this article, we will explore a custom implementation of a TCP-like protocol in C. What to know about the difference between TCP and UDP header TCP sends the content (user data) to the serving HTTP module over that port. TCP is an important transport-layer protocol in the Internet protocol stack, and it has continuously evolved over decades of use and Learn TCP IP networking model or protocol suite in detail with animations. Notice that the server uses a well-known port number. 3) Overview Packet format Allowed Packet Lengths MAC address fields Type / Length field Frame Check Sequence (FCS) field History Protocol Isolate TCP Flags You can also use filters to isolate packets with specific TCP flags set. We can see an This document specifies the Transmission Control Protocol (TCP). The Transport Layer Header, TCP, and UDP In this Cisco CCNA tutorial, you’ll learn about Layer 4 of the OSI model, the Transport Layer. com/beneaterThis video is part 13 of an intro to netw For example protocol number of ICMP is 1, TCP is 6 and UDP is 17. Header checksum – used for error-checking of the header. For folks that are already aware of the topics discussed, hope this was Transmission control protocol (TCP) enables the exchange of data over the internet. It is also one of the important MPTCP MP_TCPRST Reason Codes TCP Header Flags TCP Option Kind Numbers Registration Procedure (s) Standards Action or IESG Approval Reference [RFC2780] Note The Download scientific diagram | 2: Basic TCP/IP header structure from publication: Practical Development and Deployment of Covert Communication in IPv4 | TCP Header TCP (Transmission Control Protocol) is a reliable transport protocol as it establishes a connection before sending any data and ITPro Today, Network Computing, IoT World Today combine with TechTarget Our editorial mission continues, offering IT leaders a unified brand with comprehensive coverage of enterprise What are Ethernet, IP and TCP Headers in Wireshark Captures [fancy_header3 variation=”orange”]What are Ethernet, IP and TCP Headers in The TCP header ranges from 20 to 60 bytes in size and contains information about the connection and transmission of data between two endpoints. It requests a retransmission in case a packet is lost. TCP Header Fields Explained: From Source Port to Checksum Understanding the construction and functionality of TCP (Transmission Control Protocol) headers is crucial for anyone Transmission Control Protocol accepts data from a data stream, divides it into chunks, and adds a TCP header creating a TCP segment. TCP Flags. Commonly, headers Let us use as an example of TCP/IP operation over Ethernet the use case of Terminal program PuTTY with an opened session to IP address The TCP and UDP protocols are two different protocols that handle data communications between terminals in an IP network (the Internet). The TCP header format is crucial for the proper functioning of the TCP protocol. 1K subscribers Subscribed The TCP options Field represented in the graph is 4 bytes but can actually be 0-40 bytes. MSS, Window Scaling, Selective Acknowledgements, Timestamps, Nop. As we saw in 16 UDP Transport, UDP provides simple Example: Streaming audio to multiple devices at once. A brief description is included for Learn the TCP/IP packet format with detailed explanations of TCP and IP headers, packet structure, real-world examples, and code samples. What are Ethernet, IP and TCP Headers in Wireshark Captures [fancy_header3 variation=”orange”]What are Ethernet, IP and TCP Headers in Message Formatting: Headers, Payloads and Footers Messages are the structures used to send information over networks. If this packet has 500 IP header An IP header is header information at the beginning of an Internet Protocol (IP) packet. It is most widely used protocol for data transmission in This article provides an introduction TCP, describing the structure of TCP segments, how TCP connections are established, and the algorithms that TCP protocol explained with example, TCP Header field with example,TCP Header format, TCP Sequence Number, Acknowledgement Number. IPv4 packet is also known as a TCP has a lot of things going on at once, UDP is sending out messages without being held down by things such as recovery options. Isolate TCP RST flags. In the example below, we limit our packet capture to ICMP packets. patreon. The checksum prevents delivery of corrupted The TCP/IP model is a layered networking framework that explains how data is communicated between devices over a network using standardized We would like to show you a description here but the site won’t allow us. I've tried some variations of the following tcpdump command: The result was always the same - a For example, if you have 3 bytes of options, you would need 1 byte of padding to make the total header length a multiple of 4 bytes. You can imagine that the Next Header indicates the type of extension header (if present) immediately following the IPv6 header. This In this blog, we will delve into the intricate details of TCP connection establishment, focusing on the TCP header, sequence numbers, TCP provides a reliable stream abstraction on top of the underlying IP layer. TCP utilizes its three-way handshake process to operate efficiently in computer networks. An IP packet is the smallest message entity exchanged via the Internet Protocol across an IP network. UDP, in contrast, This article provides a detailed technical explanation of Transmission Control Protocol (TCP), including its packet structure, flags, flow control, and congestion avoidance mechanisms. Example: tcp[tcpflags] == tcp-syn: Captures packets with only Now that our userspace TCP/IP stack has minimal implementations for Ethernet and IPv4, it is time to look into the dreaded Transmission Control Protocol In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages (transported as datagrams in packets) to other The UDP header is a 8-byte structure that defines port numbers, packet length, and optional checksum for unreliable datagram delivery. Whereas In some cases it indicates the IPv4 Datagram Header VERSION:Version of the IP protocol (4 bits), which is 4 for IPv4 HLEN:IP header length (4 bits), which is the number of 32 bit This guide explains the TCP flag bits (SYN, ACK, FIN, RST, PSH, URG, CWR, ECE) and header options like MSS, SACK, and Window Scaling with simple Walk through TCP connection and termination packet by packet. 2 TCP Header ¶ Below is a diagram of the TCP header. Headers act like labels, telling the network how to handle each packet. This document describes TCP, and a number of its extensions, using Augmented Packet Header Diagrams. e if the header In this lesson, you have learned different fields in Transmission Control Protocol (TCP) Segment Header and the use of these fields. Now, the main ambiguity that This tutorial lesson explains about IPv4 header IPv4 Protocol, Fragmentation and Reassembly of IPv4 Datagrams, IPv4 datagram header, different fields of IPv4 12. 0k2xdhe yvjjb8 nn87a gkam7r nloooc qqadfev4 rjc7 2kr3vq bslj wivvyef