I. Dynamic allocation of IP address and IP address
1. Basic concept of IP address
The Internet relies on TCP/IP protocol to implement different hardware structures, different operating systems and different networks on a global scale. The interconnection of the system. On the Internet, each node relies on a unique IP address to distinguish and connect with each other. The IP address is a 32-bit binary number consisting of four 8-bit fields separated by periods to identify the TCP/IP host.
Each IP address consists of two parts: the network ID and the host ID. The network ID identifies all hosts on the same physical network. The host ID identifies each host on the physical network, so each computer on the entire Internet is identified by its unique IP address.
IP address form the basis of the entire Internet, it is so important, every networked computer has no right to set their own IP addresses, there is a unified body responsible for organizing the application of -IANA assigned a unique network ID, and the organization can assign a unique host ID to each host in its network, just as a unit does not have the right to determine the street name and house number of its own city, but can determine the office number within the unit. same.
2. static IP and dynamic IP
IP address is the address of a 32-bit binary number, in theory, possible address combinations approximately four billion (2 to the power 32) months This seems to be a big address space. In fact, according to the different number of digits of the network ID and host ID, the IP address can be divided into A (7-bit network ID and 24-bit host ID), B (14-bit network ID and 16-bit host ID), C (21 There are three types of bit network IDs and 8-bit host IDs. Due to historical reasons and differences in the development of
technical
, Class A addresses and Class B addresses are almost allotted. Currently, only C can be allocated to organizations in all countries of the world. Class address. So IP address is a very important network resource.
For an organization set up Internet services, since it hosts the opening up access services such as WWW, FTP, E-mail, usually to announce a fixed IP address, to facilitate user access. Of course, digital IP is inconvenient to remember and recognize. People are more accustomed to accessing a host through a domain name, and the domain name actually needs to be translated into an IP address by a domain name server (DNS). For example, your home page address is www.myhost.com, which users can easily remember and use, and the domain name server translates the domain name to 101.12.123.234, which is your real address on the Internet.
For most users of dial-up, due to the discrete nature of their online time and space, assign a fixed IP address (static IP) for each user is very undesirable, which will cause IP address Great waste of resources. Therefore, these users usually get a dynamic IP address each time they dial the ISP's host. This address is of course not arbitrary, but an address in the legal interval of the network ID and host ID requested by the ISP. The IP address of the dial-up user when connecting twice is likely to be different, but the IP address does not change during each connection time.
two, peer TCP /IP connection point
1. TCP /IP connection to the IP address
a running TCP /IP access to the Internet protocol computer must have a unique IP address to communicate with other computers on the network. In fact, the Internet connection can be described by four elements at any time: source IP address, source address port number, destination IP address, and destination address port number.
2. Indirect implementation of point-to-point TCP/IP connection
Since most Internet users automatically get a dynamic IP address every time they go online, this creates a direct connection between the two computers. There are certain barriers to convenient point-to-point TCP/IP connections. The solution is to connect in an indirect way, that is, both parties to the communication log in to a host that provides services at the same time, and the host establishes an indirect connection between the two parties. This method is mostly used for network telephony, network paging, and online games. With the maturity and development of technology
, this kind of network connection service can provide services such as web conferencing, multi-party calling, multi-party games, etc., which has broken through the limitations of the two-machine connection.
3. Direct implementation of point-to-point TCP/IP connection
There are many softwares that support direct TCP/IP connection, such as Microsoft's VoIP software NetMeeting, the only prerequisite is that both parties must Get the other party's dynamic IP address, or more simply, just know the IP address of the called party, which is similar to knowing the called party's phone number to establish a phone call. The key issue then is to capture and exchange their respective dynamic IP addresses, or to capture and publish their own dynamic IP addresses to wait for a call to establish a connection.
Third, the capture
capture and release
1. dynamic IP addresses dynamic IP address There are many ways and tools to achieve capture the dynamic IP address, Windows 95 /98 provides an IP configuration (WINIPCFG) utility by clicking Start-Run and typing: winipcfg in the Open box. After the program window appears, you can click Details to view it. The IP Configuration Utility allows the user or administrator to view the current IP address and other useful information related to the network configuration. The configuration information includes the host name, DNS server, IP address, netmask, and so on. One or more IP addresses can be reset. The "release" or "update" buttons release or update an IP address, respectively. If you want to release or update all IP addresses, click Release All or Update All. Other tools can also implement the query of the local IP address. Posted
2. dynamic IP address can receive dynamic IP address updates to their own home, so that all visitors can call home by the owner of the address, the establishment of point to point TCP/IP connection.
Fourth, the dynamic IP address capture publishing tools -DynamIP
know the principles, you can use tools to complete this process. DynamIP is a great dynamic capture and release tool. The main functions of DynamIP are:
1. DUN/RAS Dialer with Event Driven Program Launcher: A dial-up tool with event-driven function, which can be dialed according to user requirements or automatic timing, and can be established in new connections such as Run/close other applications driven by events such as "End of Connection" and automatically terminate the connection when network traffic falls below the set value, which is especially useful for unattended downloads of large software.
2. Uploader (Dynamic IP address poster): File upload tool (dynamic IP address publishing). DynamIP can publish your dynamic IP address on a specified web page and automatically upload the page to the server. Of course, it can also be used to update and upload any file, for example, to upload a graphic file periodically, and the file is automatically taken by a digital camera, so the homepage becomes a live broadcast page.
3. DIPS ClIEnt: DIPS client software, DIPS (Dynamic IP Server) is the abbreviation of dynamic IP server. After applying for a free account, the dynamic IP server can display a dynamic pointing to you in the homepage. The URL of the IP is in the form: http://postmodem.com/dips/<
; your account name>.
This feature allows online users to access your local home page via this URL, which is a web server (such as a personal web server) installed on a local host. This feature is especially important when you want to debug the home page or if you can't find a free homepage server that provides satisfaction, or if you think that uploading the homepage is too time-consuming. The current virtual domain name service is different. The virtual domain name service requires you. The home page must be placed on a home page server with a fixed domain name before it can provide transfer access, while the dynamic IP server can keep track of your dynamic IP and transfer visitors to your local web server. As long as you are connected to the network and your local web server is running, DynamIP can automatically determine if your DIPS information needs to be updated to a dynamic IP server. With DIPS, users can chat on the web without uploading any files.
4. POP mail checker: E-mail check, can check up to 5 different POP3 accounts, and prompts with visual or voice signal after new mail arrives, automatically runs E-mail client software to win the letter .
5. IP chat: peer-to-peer IP chat, similar to IRC, but does not require any IRC server, DynamIP can scan within the user-specified IP address range, you can broadcast messages to all chat members or specific IP addresses, you You can greet other chat members to get the attention of the other party and establish a private chat. DynamIP supports Microsoft NetPhone software MS NetMeeting.
6. WEBchat: Web chat. Your homepage visitor can use the browser to talk directly to you. Even if the other party does not have DynamIP installed, the page will be dynamically updated by DynamIP. The browser must support forms, Netscape and Internet Explorer, and no doubt supports forms. The visitor can fill out the statement in the forms and press the submit button, which is sent to your computer (dynamic IP captured with DynamIP). You can work with feature 3 to implement local web chat, so you don't have to upload the home page to any server.
7. HTTPscan: HTTP scanning. DynamIP can scan within a user-specified IP address range and generate a list of all searched HTTP servers in a hypertext file format. One use is that when you do a peer-to-peer IP chat with someone, you can immediately access each other's home page.
8. PC Clock Synchronizer: Clock synchronization. DynamIP can get accurate date and time from an NTP server to calibrate your machine clock, and can also be used to partially solve the "millennium bug" problem.
V. Installation and setup of DynamIP
1. Installation of DynamIP
There is only one condition for the installation of DynamIP, that is, in your Windows system. There must be a runtime library of VB
6.0—MSVB
VM60.DLL. This file is not included in the DynamIP package. Users must download it from the official Microsoft website VB
, the file name is Vbrun60new.exe, which is an automatic installation file with a file length of 1MB.
DynamIP set of basic principles
2. DynamIP is very simple, DynamIP will use the template file (Template) in the form of parameters to update a local file that contains your current Dynamic IP address, then DynamIP automatically uploads the file to your personal home page server, so other users accessing your home page can use the dynamic IP address information on the page to connect with you to implement various web applications; or DynamIPS updates you The DIPS information is sent to the dynamic IP server, and all users accessing the server can be transferred to your local web server. So when setting up and preparing DynamIP, everything is done around this template file and your dynamic IP address. The main function of
DynamIP are Uploader file upload tool (dynamic IP address released), this article will introduce DynamIP as an example of the settings, set various other features are similar. Run DynamIP and select setup-uploader to enter the setup window. The parameters are as follows:
Active: Turn this service on/off;
Remote Host :