tcp ip ports and protocols

Methods for detecting TCP ports in php This example describes how to implement TCP port detection in php. Share it with you for your reference. The details are as follows: This program can check whether the current port is available: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Class Hea

request or response program. After the frame is used, the original data before encapsulation is finally sent to the target service. Iv. Port Well-known ports: from 0 to 1023, which are allocated and controlled by IANA and bound to some services. Registered Ports (Registered Ports): from 1024 to 49151. These Ports are

of the earliest protocols used on TCP/IP networks and the Internet, which belongs to the application layer of the Network protocol group. The FTP client can issue commands to the server to download files, upload files, and create or change directories on the server.2 N-Layer switching technology2.1 Two-layer switchingSwitching principle: The end-to-end data exch

I. Monitoring requirements: Remote monitoring of custom TCP ports on Windows Servers 1. Linux machines are relatively simple. Use the check_tcp plug-in (the steps are omitted) 2. Windows machine, using the check_nt plug-in, check_nt for detailed usage see http://nagiosplugins.org/man/check_nt A. First install nsclient ++ B. Edit /Usr/local/Nagios/etc/objects/commands. cfg configuration file Add the followin

The example in this article describes how Python detects TCP ports on remote servers. Share to everyone for your reference. Specific as follows: Python detects the code of the remote server TCP port, which can be used as a server monitoring utility #!/usr/bin/env python #coding: utf-8 #filename: tcp.py ' Author:gavingeng date: 2011-12-14 09:35:59 ' Import Socke

to the OSI reference Model of the physical layer, the data link layer and the TCP/IP model of the network interface layer corresponding to the principle of convenient understanding, Often take a compromise approach, using a five-layer protocol principle architecture, as shown in Relationship between layers and layers Layers and layers are called each other, and the same layer communicates

) the process of 1.TCP/IP protocol data Encapsulation Take the transport layer adopt TCP or UPD, the network layer uses the IP, the link layer uses the Ethernet as the example, may see the TCP/IP message encapsulation process

. TCP Message structure:The header of the TCP segment has a fixed portion of the first 20 bytes, and the following 4n bytes are the fields that are added as needed and are the complete TCP message structure:20-byte fixed part, each field function description: Source and Destination ports : 2 bytes each,

The linux OSI Layer-7 model, TCP/IP protocol stack, and the structure of each layer reveal big secrets. The osi protocol stack When I learn Linux, I know the OSI model even if I am a little cute. What ?! You don't know !!! Okay, this secret is taken away. Thank you ~~~ I,Two protocols (1OSI protocol model (layer-7) International ProtocolPDU: The data unit transm

To change your system to a copper wall, close these ports, Mainly include TCP 135, 139, 445, 593, 1025, and UDP ports 135, 137, 138, and 445, Some popular Backdoor Ports (such as TCP 2745, 3127, and 6129) and remote service access port 3389. The following describes how to di

with the application interface for demonstration purposes. Common protocols include HTTP, HTTPS, FTP, TELNET, SSH, SMTP, POP3, etc. layer-2, TCP/IP layer-4 model peer-to-peer communication encapsulation sub-Port q (WellKnown Ports ): from 0 to 1023, these ports are allocate

that identifies the send, which is the IP address in the TCP/IP protocol. Java provides a class inetaddress for us to use. Port numberThe logical address used to identify the process, and the identity of the different processesPhysical port Nic Portlogical ports We're talking about logical ports.each network program w

To write a network program, you must use socket. This is what programmers know. In addition, during the interview, we will also ask if the other party will be able to program the socket? In general, many people will say that socket programming is basically listen, accept, send, write and other basic operations. Yes, just like common file operations, as long as they have been written. For network programming, we must also call it TCP/

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