wholesale body piercing jewelry china What are the so -called ports on the computer and how do you check your port?
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wholesale jewelry to sell The "port" of the computer is an English Port translation, which can be considered as an exit of computer communication between computers and external communication. The ports of the hardware field are also called interfaces, such as: USB port, serial port, etc. The port of the software field refers to the network facing the communication protocol port facing the connection service and non -connected service. It is an abstract software structure, including some data structures and I/O (basic input and output) buffer.
It ports can be divided into 3 categories:
1, recognized port (Well Known Ports): from 0 to 1023, they are closely bound to some services. Generally, the communication of these ports clearly shows the agreement of a certain service. For example: Port 80 is always http communication.
2, registration port (Ports): from 1024 to 49151. They are loosely bound to some services. In other words, many services are bound to these ports, which are also used for many other purposes. For example: many system processing dynamic ports start from about 1024.
3, dynamic private (Dynamic and/or Private Ports): from 49152 to 65535. Theoretically, these ports should not be allocated for services. In fact, machines usually allocate dynamic ports from 1024. But there are exceptions: SUN's RPC port starts from 32768.
extension information
If ports in the invasion
someone used to compare the server as a house, and to compare the port to This is a good metaphor if you don't consider details to different rooms (services). To occupy this house, the invaders must break the door (physical invasion separately), so for the intruder, knowing how many doors are opened by the house, what kind of door is? It is important.
The invaders usually scan the port of the target host with a scanner to determine which ports are open. From the open port, the invaders can know what services the target host provides, and then guess the possible vulnerabilities that may exist Therefore, scanning ports can help us better understand the target host, and for administrators, scanning the open port of the machine is also the first step in safety prevention.
Reference materials Source: Baidu Encyclopedia-Port
Reference materials Source: Baidu Encyclopedia-Computer port
jewelry wholesale suppliers tucson az Computer "port" is a righteous translation of English Port, which can be regarded as an exit of computer communication between computers and external communication. The ports of the hardware field are also called interfaces, such as: USB port, serial port, etc. Port in the field of software generally refers to a communication protocol port facing connection services and non -connected services in the network. It is an abstract software structure, including some data structures and I/O (basic input and output) buffer.
It first understanding of the main characteristics of connection and non -connection protocols ( -) facing connection services are: three stages for connection services: before data passings, establish connections, after connection establishment, and then then After transmitting data, after the data is transmitted, the connection is released. Facing connection services can ensure the order of data transmission and the reliability of transmission. The characteristics of non -connection services are: the data -free service is only the transmission data stage. Eliminate other expenses except data communication. As long as the entity is active, it is also active without receiving entities. Its advantages are flexible, convenient and fast, and are especially suitable for transmitting a small amount of sporadic packets, but the non -connection service cannot prevent the loss, repetition or ordering of the message.
The concepts of "facing connection services" and "no connection services" are differentiated. Especially simple and image examples are: calling and writing. If two people want to call the phone, they must first establish a connection-dial-up, wait for the answer before they can pass the information to each other, and finally release the connection-hang up. Writing the letter is not so complicated. After filling in the address name, throw it directly to the postbox, and the receiver can receive it. The TCP/IP protocol is not connected in the network layer (how does the data packet only send to the Internet, how to transmit and reach it, and whether it is managed by the network device). The "port" is the content of the transmission layer, which is connected. The ports that are lower than 1024 are defined, and they correspond to some services common on the Internet.
This services can be divided into two types: use TCP ports (for connecting such as connecting) and UDP ports (without connectors such as writing).
The communication port that can be named and addressing in the network is a distribution resource for the operating system. The seven -layer protocol from the Internet OSI (open system interconnection model,) the biggest difference between the transmission layer and the network layer is that the transmission layer provides process communication capabilities. The final address of network communication includes not only the host address, but also some kind of described process. Identification. Therefore, the protocol port proposed by the TCP/IP protocol can be considered as a identifier of the network communication process.
The application (generally referred to as: processes after adjusting memory operation) After the system calls a connection with a port (binding), the data passed to the port to the port is correspondingly corresponding to the portion of the port. The data received by the process, the data sent to the transmission layer accordingly output from the port. In the implementation of the TCP/IP protocol, the port operation is similar to the general I/O operation. The process obtains a port, which is equivalent to obtaining the only local I/O file. Each port has an integer descriptor called the port number, which is used to distinguish different ports. Since the TCP/IP transmission layer TCP and UDP protocols are two completely independent software modules, their respective port number is also independent of each other. For example, TCP has a port 255, and UDP can also have a port 255, and the two do not conflict. There are two basic distribution methods of the port number: the first is called a global allocation. This is a centralized distribution method. It is recognized as an authoritative central institution to uniformly allocate according to the user's needs and publish the result to the public. The second is the local distribution. , Also known as dynamic connection, that is, when the process needs to access the transport layer service, apply to the local operating system. The operating system returns the only port number of the local area. Certainly). The distribution of TCP/IP port number combines the above two methods. The port number is divided into two parts, and a small number of as a reserved port is allocated to the service process in a global way. Each standard server has a global recognized port called Zhou Zhikou. Even on different machines, its port number is the same. The remaining is the free port to allocate in a local way. TCP and UDP stipulate that ports smaller than 256 can be used as reserved ports.
The portrait can be divided into 3 categories:
(1) Conflying port (): from 0 to 1023, they are closely binding (binding) to some services. Generally, the communication of these ports clearly shows the agreement of a certain service. For example: Port 80 is always http communication.
(2) Registration port (): from 1024 to 49151. They are loosely bound to some services. In other words, many services are bound to these ports, which are also used for many other purposes. For example: many system processing dynamic ports start from about 1024.
(3) Dynamic and/or private ports (/): from 49152 to 65535. Theoretically, these ports should not be allocated for services. In fact, machines usually allocate dynamic ports from 1024. But there are exceptions: SUN's RPC port starts from 32768.
The system manager can "redirect" port: a common technology is to redirect one port to another address. For example, the default HTTP port is 80, and many people redirect it to another port, such as 8080. If this is changed, you should use this address wwd.3322: 8080/net/port (of course, this is only theoretical example). The realization direction is to hide the recognized default port to reduce the destructive rate. In this way, if someone wants to attack a recognized default port, a port scan must be performed first. Most port redirects are similar to the original port. For example, most HTTP ports change from 80: 81,88,8000, 8080, 8888. The port of the same POO was originally 110 and was often redirected to 1100. There are also many situations that are selected in statistics, like 1234, 23456, 34567, etc. Many people have other reasons to choose strange numbers, 42, 69, 666, 31337. Recently, more and more remote control Trojan (,, RATS) uses the same default port. For example, the default port of Netbus is 12345. Blaker.swopes pointed out that there is another reason to use the redirect of the redirect. On the UNIX system, if you want to listen to the port below 1024, you need to have root permissions. If you don't have ROOT permissions and want to open Web services, you need to install it on a higher port. In addition, some ISP firewalls will block the communication on the low port, so that even if you have the entire machine, you still have to redirect the port.
The list of common ports for computers:
1 transmission control protocol port service port service multi -road switch selector
n2 Management utility
n3 Compression process
5 remote operation login
7 back (Echo)
9 discard
11 online users
n
13 Time
15 netstat
17 Daily reference
18 message sending protocol
n19 character generator
20 file transmission protocol (default data port)
21 file transmission protocol (control)
22 SSH remote login protocol
n23 Telnet terminal simulation protocol
24 Reserved the personal mail system
25 SMTP Simple mail sending protocol
27 NSW user system on -site engineer
n29 msg ICP
31 MSG verification
33 Display support protocol
35 Reserved to personal printer service
37 time
n n R n38 Route access protocol
39 resource positioning protocol
41 graphics
42 WINS console service
43 "WHO" "WHO" "WHO" IS service
44 mpm (message processing module) logo protocol
45 message processing module
46 message processing module (default verse)
47 ni ftp
48 digital audio background service
49 tacacs login hosting protocol
50 remote email checking protocol
n51 IMP IMP (Interface information processing machine) Logic address maintenance
52 Schola network service system time protocol
53 domain name server
n54 Schola network service system bill exchange r
55 ISI graphics language
56 Schola network service system verification
57 Reserved personal terminal access
58 Schole network service system mail r r r r r r
59 Reserved personal file service
60 is not defined
61 ni mail?
62 asynchronous communication adapter service
63 WHOI S
64 communication interface
65 Tacacs database service
66 oracle SQL*net
n67 guidance protocol service side
68 guide program protocol client
69 small file transmission protocol
70 information retrieval protocol
n71 remote operation service
72 remote operation service
73 Remote operation service
74 remote operation service
75 reserved to dial the service
n76 Distributed external object storage
77 reserved for individual remote operation input service
78 correction TCP
79 finger (query remote host online user and other information)
80 Global Information Network Supercrapers Transmission Protocol (: 8080.
Portal vulnerabilities: Port 8080 can be used by various virus programs. For example, brown orifice (BRO) Troy Trojan virus can use port 8080 to completely remotely controlled infected computers. In addition, Ringzero Trojan can also use this port to attack.
Ip operation suggestions: Generally, we use port 80 to browse web. In order to avoid the virus attack, we can turn off the port.
: 21
Service: FTP
Instructions: The port open by the FTP server is used for uploading and downloading. The most common attacker is used to find a way to open the ANYMOUS FTP server. These servers have readable directory. Trojan Doy Trojan, Fore, Invisible FTP, Webex, WinCrash, and Blade Runner's port.
: 22
Service: SSH
Instructions: The connection of the established TCP and this port may be to find SSH. There are many weaknesses in this service. If configured into a specific mode, many versions of the RSAREF library will have many vulnerabilities.
: 23
Service: Telnet
Instructions: Remote login, the invaders search for remote login UNIX services. In most cases, scanning this port is to find the operating system of the machine running. There are other technologies, and the invaders will also find a password. Trojan Tiny Telnet Server opens this port.
: 25
service: SMTP
Instructions: The port open by the SMTP server is used to send emails. The invaders are looking for the SMTP server to convey their SPAM. The intruder's account is closed, and they need to connect to the high-bandwidth E-mail server to pass the simple information to different addresses. Trojans Antigen, Email Password Sender, HAEBU COCEDA, Shtrilitz Stealth, WinPC, Winspy are all open this port.
: 80
Service: http
Instructions: Used for web browsing. Trojan Executor opens this port.
: 102
Service: MESSAGE Transfer Agent (MTA) -X.400 Over TCP/IP
Instructions: Message transmission proxy.
: 109
Service: Post Office Protocol -Version3
Instructions: POP3 server opens this port for receiving emails, client access Server email service. Pop3 services have many recognized weaknesses. There are at least 20 weaknesses over the overflow of the username and password switching buffer, which means that the intruder can enter the system before the actual landing. After successful landing, there are other buffer overflow errors.
: 110
Service: all ports of the RPC service of Sun
Note: Common RPC services include RPC.Mountd, NFS, RPC. STATD, RPC.CSMD, RPC.TTYBD, AMD, etc. Port: 119
Service: Network News Transfer Protocol
Instructions: News news group Transmission protocol, carrying userNet communication. The connection of this port is usually looking for the Usenet server. Most ISP restrictions, only their customers can access their news group server. Opening the news group server will allow post/read anyone's posts, access the restricted news group server, and anonymous posts or send spam.
: 135
Service: Location Service
Instructions: Microsoft runs DCE RPC END-POINT MAPPER on this port for its DCOM service. This is very similar to the function of the Unix 111 port. Use DCOM and RPC services to register their positions with End-Point Mapper on the computer. When the remote client is connected to the computer, they find End-Point Mapper to find the location of the service. Is the port of Hacker scan the computer to find the Exchange Server running on this computer? What version? There are also some DOS attacks directly targeting this port.
port: 137, 138, 139
service: Netbios name service
Instructions: 137, 138 are UDP ports, when the neighbors are used online neighbors online neighbors Use this port when transmitting files. Port 139: Try to get Netbios/SMB services through the connection to this port. This protocol is used for Windows files and printers sharing and Samba. And Wins also use it.
: 161
Service: SNMP
Instructions: SNMP allows remote management equipment. All configuration and running information are stored in the database, and this information can be obtained through SNMP. Many administrators' error configurations will be exposed to Internet. CACKERS will try to access the system with the default password PUBLIC and Private. They may test all possible combinations. The SNMP package may be directed to the user's network
what is a port?
It before starting with the port, let's talk about what Port? I often heard on the Internet, "How many PORT has I opened, will it be invaded! Intersection Or said, "Will it be safer to open that port? Another, what PORT should my service correspond! Intersection "Ha ha! It's amazing! Why are there so many strange PORTs on a host? What is this Port? Intersection
Since the service functions of each network are different, it is necessary to give different packets to different services to deal with it, so when your console opens the FTP and WWW service at the same time Then the data packet sent by others will be handled by the PORT number on TCP or the service of the FTP or WWW. Of course, it will not be chaotic! (Note: Hey! Some friends who rarely come into contact with the Internet often ask: "Well! Why do your computers have as many services as FTP, WWW, E-mail at the same time, but people pass the information, how do you know your computer know How to judge? Does the computer really misjudge?! "Do you know why?! Yeah! It’ s because of different PORT! You can think so, one day, you have to go to the bank to save money, and that bank will be that bank, so that bank will be that bank. It can be imagined as a "host", and of course, the bank cannot have only one business, and there are quite a few windows in it. Then when you enter the door, the service staff at the door will ask you, "Hi! You! Okay! What do you have to do? "You said to him," I want to save money! ", The waiter will then tell you:" Drink! So please go to the No. 3 window! ! "At this time, you should never run to other windows?!" "These windows can be imagined as" Port "! So! Each service has a specific port on monitoring! You don't need to worry about the computer The problem that will be misjudged!)
· Each TCP online must initiate a request from one end (usually client). This Port is usually randomly selected by a PORT number greater than 1024! Its TCP packet will set (and only) SYN flag below! This is the first packet of the entire online package;
· If the other end (usually Server) accepts this request (of course, special services need to be carried out in special ports, such as FTP PORT 21), will send the second packet of the entire online online! In addition to the SYN flag, the ACK flag has also been set, and the resource is established on the side of this machine at the same time;
· then the request end to obtain the server side After the first response packet, the other party must be confirmed to confirm the packet. At this time, the packet only brings the ACK flag (in fact, all the packets in the succession of the succession must bring the ACK flag);
· Only when the server receives the request -side confirmation (ACK) packet (that is, the third packet of the entire online), can the two ends of the two ends be officially established. This is the principle of the so-called TCP online three-stage grip.
After three -way grip, huh! The port on your client is usually a random Port higher than 1024. As for the host side, it depends on which port of the service at the time. For example, WWW selects 80 and FTP uses 21 as a normal online channel!
In short, the ports we are talking about here are not the I/O port of computer hardware, but the concept of software form. Tools provide different types of service types. The TCP port is the UDP port. When communicating between computers, there are two ways: one is that after sending information, you can confirm whether the information can be reached, that is, there is a way to respond. Most of the ways are used to respond. , Do not confirm whether the information is reached, most of this method adopts UDP protocol. Corresponding to these two protocols, the port provided by the two protocols is also divided into TCP ports and UDP ports.
. If the attacker uses software to scan the target computer and get the port of the target computer, you will also understand those services that the target computer provides those services. We all know that there must be a loophole in service software to provide services. Based on these, attackers can reach a preliminary understanding of the target computer. If the port of the computer is opened too much, and the manager does not know, then there are two cases: one is to provide a service and the manager does not pay attention. For example It may not be noticed; one is to install a Trojan horse with the attacker and communicate through a special port. Both situations are very dangerous. In the final analysis, the administrator does not understand the services provided by the server, which reduces the system security factor.
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"port"?
In network technology, ports (Port) have several meanings. The port of the hub, switch, and router refers to interfaces connecting other network devices, such as port RJ-45, Serial port, etc. The ports we refer to here do not refer to the port in the physical sense, but the port in the TCP/IP protocol, which is the port in the logical sense.
So what does the port in the TCP/IP protocol refer to? If the IP address is compared to a house, the port is the door to the house. There are only a few real houses, but there can be as many as 6,5536 ports of an IP address! The port is marked by the port number. The port number is only an integer, and the range is from 0 to 65535.
What is the use of ports? We know that a host with an IP address can provide many services, such as web services, FTP services, SMTP services, etc. These services can be achieved through 1 IP address. So, how does the host distinguish different network services? Obviously, you cannot rely on the IP address, because the relationship between IP address and network service is a pair of relationships. In fact, different services are divided into different services through the "IP address port number".
The attention should be noted that the port is not one -to -one. For example, when your computer visits a WWW server as a client, the WWW server uses the "80" port to communicate with your computer, but your computer may use ports such as "3457", as shown in Figure 1.
If according to the corresponding protocol type, there are two ports: TCP port and UDP port. Since the two protocols of TCP and UDP are independent, their respective port number is also independent of each other. For example, TCP has 235 ports, and UDP can also have 235 ports. The two do not conflict.
1. The Zhou Zhi port (Well Known Ports)
The weekly port is a well -known port number, the range is from 0 to 1023, of which 80 is allocated to the WWW service, and the 21 port distribution is allocated. Give FTP service, etc. When we enter a URL in the IE address bar (for example), there is no need to specify the port number, because the port number of the WWW service is "80" by default.
The network service can use other port number. If it is not the default port number, you should specify the specified port number on the address bar. Add the port number. For example, using "8080" as the port of WWW service, you need to enter ": 8080" in the address bar.
but some systems protocol using fixed port number. It cannot be changed. For example, port 139 is specifically used for communication between Netbios and TCP/IP, which cannot be changed manually.
2. Dynamic port (Dynamic Ports)
The range of the dynamic port is from 1024 to 65535. The reason why it is called a dynamic port is because it generally does not fixed a certain service, but dynamically allocated. Dynamic allocation means that when a system process or application process requires network communication, it applies for a port to the host, and the host allocates one to use it from the available port number. When this process is closed, the occupied port number is released.
Mo. How to view port
The portable ports of a server, how to view the port? There are two ways: one is to use the system built -in command, and the other is to use a third -party port scanning software.
1. View port status with "NetStat -N"
In Windows 2000/XP, you can use the "NetStat -AN" under the command prompt to view the system port status, and You can list the port number and status of the system being open.
2. Scanning software with a third -party port
The third -party port scanning software. Although the interface is very different, the function is similar. Here is an example of "FPORT" (can be downloaded to/soft/cCE) as an example. "FPORT" is used under the command prompt, and the running results are similar to "NetStat -AN", but it can not only list the port slogan and type that is in use, but also use which application is used by the port.
jewelry raw material wholesale Port refers to some registers in the interface circuit. These registers are used to store data information, control information, and status information, respectively. The corresponding ports are called data ports, control ports, and state ports.
The method of viewing your own port is as follows:
1, switch to the desktop, press the Win x combination key, select the "command prompt (administrator)" command;
2, if it is just just Select the "command prompt" command, then the later operation may be errors;
3, after opening the DOS window, generally we will enter the "netstat" command to view the simple statistical information. ;
4, when entering the "netStat -Nao" command, you can display the PID process serial number on the right to the right, so as to use the command to directly end the program; Details;
6. After discovering these abnormal ports and programs, you can end the process tree first, and further perform other detailed operations:
7, and if you need specific surveillance and control ports, you need to need Third -party software is used. Such software such as Jusheng network management can intuitively and quickly achieve port monitoring and control.
cheap wholesale mens jewelry Run -CMD -NetStat -AN
chain for jewelry making wholesale in india Run -CMD -NetStat -ANO