dnp3 packet format

number of ICMP packets will form an "ICMP Storm", so that the target host consumes a lot of CPU resources processing, tired. * http Grab bag $tcpdump –xvvennss 0–i eth0 tcp[20:2]=0x4745 or tcp[20:2]=0x4850 get : (E), (G) http:h:48 t:54 ASC code 65~90 to 26 uppercase English letters Listen for packets that specify the contents of the Ip/tcp field $ Tcpdump ' ip[2:2]>3 ' //Intercept packet//ip[2 with a native IP

calculated. By shortening the cycle time of the micro-frames, it is possible to reduce the need for buffer memory at high speed.As shown in 1, the high-speed root hub will use an extra SOF to transmit 8 micro-frames. Some books will call this high-speed SOF, and the other name Usof. This increased micro-frame also brings more sophisticated control to high-speed connections.Figure 1 USB frames and Micro FramesIn addition, the diagram shown in 2 is used to illustrate the

be considered as an atomic operation only when reading a single byte. In this way, when the length of a data packet is greater than one byte, it cannot be read once by default. Therefore, a state machine is generally used to process network data streams. This state machine can be implemented very easily. The format of Length + Type + content can be seen as three States of the state machine. In the main log

It mainly analyzes the packet format of VLAN. At the same time, the application of vconfig command is explained. pc:10.10.107.168 ap:10.10.107.231 (eth0.100) 1: Add VLAN, use Vconfig. ~# Vconfig BusyBoxv1.10.3 (2012-09-23 02:13:20 CST) multi-call binary Usage:vconfig COMMAND [OPTIONS] ... Create Andremove Virtual Ethernet Devices Options: add [Interface-name] [vlan_id] REM [Vlan-name] Set_flag [Interface

It mainly analyzes the packet format of VLAN. At the same time, the application of vconfig command is explained. pc:10.10.107.168 ap:10.10.107.231 (eth0.100) 1: Add VLAN, use Vconfig. ~# Vconfig BusyBoxv1.10.3 (2012-09-23 02:13:20 CST) multi-call binary Usage:vconfig COMMAND [OPTIONS] ... Create Andremove Virtual Ethernet Devices Options: add [Interface-name] [vlan_id] REM [Vlan-name] Set_flag [Interface-n

Advertising RouterRouter ID of the router advertised by the originating LSA5. Link-State Update packets650) this.width=650; "Style=" Background:url ("/e/u261/lang/zh-cn/images/localimage.png") no-repeat Center;border : 1px solid #ddd; "src="/e/u261/themes/default/images/spacer.gif "alt=" Spacer.gif "/>OSPF packets are not allowed to leave the network from which they originated, a link-state packet can carry one or more LSA, but these LSA are only rou

ArticleDirectory IPv6 Message format Comparison between IPv4 and IPv6 Headers IPv6 Message format Version (4-bit): IP version. The value of this field is 6. Traffic class (8-bit): traffic classification, similar to the TOS of IPv4 Headers Flow Label (20-bit): Flow Label, used to mark a stream of IPv6 Packets Payload length (16-bit): the length of the payload. The exte

. S is that when the typeA value of 24 ~ 31 means that this is a special format of the NAL unit, while in H. 1~23 is a valid value.Stap-a Single-time combo packageStap-b Single-time combo packMTAP16 Multi-time combo packMTAP24 Multi-time combo packFu-a Shards of cellsElements of Fu-b shards30-31 Not definedPossible types of structures are:1. Single NAL unit modeThat is, a RTP packet consists of only one com

Ipv6 Protocol packet format 1. ipv6 basic format ipv6 packet format from the perspective of simplicity, it is simpler than ipv4, and the length of the ipv6 basic header is fixed. Compared with ipv4, ipv6 removes some headers and gets all of these headers to the end of the ex

TCP message format is as follows:Figure 2 TCP Message FormatSource and destination portsUsed for multiplexing/multiplexing of data from or to upper-layer applications, it is understood that ports are used to identify different processes on the same computer.Serial number and confirmation numberThese two fields are a critical part of the TCP reliable transport service, and the serial number is the byte stream number of the first bytes of the

address length are 6 and 4, respectively. This corresponds to the ARP packet format. The next two bytes of OP indicate whether the current package is a request package or a response package. The corresponding values are 0x0001 and 0x0002, respectively. The original data is 00 01, so this is a request packet, and the six bytes are the sender's MAC address 00 0C F

To better understand a network protocol, we must clearly define and structure it. We have also explained the definition of the DHCP protocol. Here we will analyze the DHCP packet format. DHCP packet format Let's introduce the DHCP packet

In order to better handle the refresh of the route on the dial-up network, the packet format is improved and expanded according to the RFC/1581/15822091/2092 standard. The packet modification mainly supports three new packet grouping types, which are marked in the packet com

We have introduced the basic content of DHCP. Here we will discuss in detail the knowledge and problems related to the DHCP packet format. DHCP packet format Let's introduce the DHCP packet format, 1 OP (1)

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 bett

Addressvariable part of IP datagram header :The variable part of the IP capital is an optional field. Option fields are used to support troubleshooting, measurement, and security measures, and are rich in content. This field is variable in length, ranging from 1 bytes to 40 bytes, depending on the item selected.Some options require only 1 bytes, and it includes only 1-byte option codes. However, there are several options that require multiple bytes, which are stitched together, with no delimite

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,