【 Weak current college 】 thoroughly know the classification of the port

Port of port-classification according to the classification of its reference objects have different partition method, from the port of nature, can generally be divided into the following three categories:

(1) recognized port (WellKnownPorts): this type of port often referred to as "commonly used ports. This type of port the port number from 0 to 1024, they are closely bound to a specific service. Usually these ports communication clearly indicates a service agreement, this port is not to redefine its role object. For example, port 80 is actually always used by the HTTP communication, and 23, the port is dedicated for the Telnet service. These ports are usually not like Trojans hacker program utilization. In order to make everyone on these commonly used ports more understanding, later in this chapter will be more opposite the port should be the list of services for understanding and reference.

(2) registered ports (RegisteredPorts): the port number from 1025 through 49151. They are loosely bound to some services. It is said that there are many services bound to these ports, the ports are the same for many other purposes. Most of these ports is not clearly defined service object, different programs can be defined according to the actual needs, such as back to introduce remote control software and Trojans programs will have these ports defined. Remember these common procedures for ports in the Trojan horse protection and killing is necessary. Common trojans are using ports in the back will have a detailed list.

(3) dynamic and/or private ports (Dynamicand/orPrivatePorts): the port number from 49152 65535. In theory, should not be the usual service distribution in these ports. In fact, some are more special procedures, in particular some Trojan program is like using these ports, because these ports are often not noticed, easily concealed.

If according to the provided services, the port can be divided into "TCP port" and "UDP port".

Because computers communicate General both communication protocol. Preceding the introduction of "connecting mode" is a direct and receiving parties, send information later, you can verify your message arrives, this way most of the TCP protocol; the other is not directly connected with the receiver, but the information sent over the Internet, regardless of whether the arrival information, that is described earlier in "no connection". This way most of the UDP protocol, IP protocol is a connectionless manner. Corresponding with the above two communication protocols of the services provided by the port, which is divided into "TCP port" and "UDP port".

Use the TCP protocol for common ports mainly has following several kinds:

(1) FTP: file transfer protocol has been defined, use port 21. Often say certain computer open the FTP service is initiated the file transfer service. Download the file, upload your home page, are used to the FTP service.

(2) Telnet: it is a port for a remote login, users can take their identity to connect remotely to your computer, this port can provide a DOS mode of communication services. If the previous BBS is pure character interface, support BBS Server 23 port is open, the external service provision.

(3) SMTP: defines the Simple Mail Transfer Protocol, now many mail servers using this protocol used to send the message. As common in free message service is the messaging port, so in the email settings often see this SMTP port set the bar that is open to the server, port 25.

(4): it is the POP3 and SMTP, POP3 is used to receive mail. Typically, the POP3 protocol is used by 110 port. It is said that as long as you have the appropriate program using the POP3 Protocol (such as Foxmail or Outlook), you can not login to the Web interface, directly into the mailbox mail program can receive messages (such as is 163 mailbox there is no need to first go to the NetEase Web site, and then enter your email to the recipient).

Use UDP port common are:

(1) HTTP: this is the most widely used, it is often said of the Hyper Text Transfer Protocol ". Surf Web pages, you will have to provide Web resources of the computer, open port 80 in order to provide the service. Often say "WWW service", "Web server" is the port.

(2) DNS services for domain name resolution, this service in WindowsNT system used most frequently. On the Internet, each computer has a network address corresponding to this address is often said that the IP address it to pure digital + "." Of representation. However this was inconvenient memory, so a domain name, access to your computer when you only need to know about domain names, domain names and IP addresses between the transformation by the DNS server. DNS is 53, the port.

(3) SNMP: simple network management protocol, using port 161, is used to manage network devices. Because many network devices, connectionless service that reflects its advantages.

(4) OICQ: OICQ program accepts both services, provide services, so two chat talents are equal. OICQ using a connectionless protocol, it is said that it uses UDP protocol. OICQ server is using port 8000, listens for messages to arrive, the client uses the 4000, port, send a message to the outside. If the port is in use (there are a lot of people at the same time and a few friends chat) that is added to the order. In the computer's 6 million more than one port, usually port number is 1024 within these commonly used ports, as commonly used ports corresponding to the serviceTypically are fixed. Table 1 is the default port that the server does not allow the change, general communication process are mainly used to these ports. Service type default port service type default port Echo7Daytime13FTP21Telnet23SMTP25Time37Whois43DNS53Gopher70Finger79WWW80POP3110NNTP119IRC194 another proxy server common the following ports:

(1) .HTTP protocol proxy server common port number: 8080/80/3128/8081/9080
(2) .SOCKS agent protocol servers commonly used port number: 1080
(3) .FTP protocol proxy server common port number: 21
(4) .Telnet Protocol proxy server common port: 23