Regarding Internet connection service provided by ISP to customers, there are many types of services:
Direct Internet connection (eg leased-line) For organizations that need high-speed, stable Internet connection, you can hire direct connection services. An organization's leased-line network will always connect to the Internet via its own transmission line. T These organizations will be provided by ISPs for a static IP address space. With this IP address space, organizations can assign static addresses to servers and self-maintain service servers such as ftp, mail, web, dns ... because the organization's network is constantly connected to the Internet with High connection speed and stability. If you do not self-maintain servers, these organizations may also be able to lease services that run on ISP servers.
Internet connection service indirect Typically, the service connects to the Internet through dialup. With this type of service, the user connects to the Internet using a telephone line and does not regularly connect to the Internet, the user will disconnect when no longer needed. This type of connection has a slow transfer rate, no static IP address, and the subscriber only uses it to access the Internet without maintaining a service provider, which is the host that requires continuity in the connection. connected. To use services such as email or web (with a separate domain name), the user must register for the service at the ISP (web hosting, mail hosting ...), ie hire the service on the ISP's server.
High-speed Internet (ADSL) service: This is a form of Internet connection that uses a telephone line but has a high Internet connection speed and is connected constantly, ie the organization's network is always connected to the Internet (always-on). If the ADSL subscriber is statically assigned to a static IP address, then it is possible to use this persistent connection to maintain service servers such as ftp, mail, web, dns, etc., using the leased-line connection. . However, to save IP address space, not only dialup connections but also ADSL services, providers also use dynamic addressing. This makes customers using ADSL high-speed service can only improve the speed of Internet access, but can not maintain self-service servers such as mail, ftp, web as the object rental. Direct connection leased-line.
Dynamic address allocation (dynamic IP)
Typically, when a subscriber connects to the Internet, the ISP that subscribes to the Internet service will provide this connection (in fact, the server is responsible for allocating the address. For example, a DHCP server in dialup or BRAS in a service provider's ADSL service automatically attaches to the subscriber's connection an unused address in a shared address pool that the ISP provides for Subscriber indirect connection (dynamic connection) called pool area. This allocated address is only used during this period of connection to the Internet, when the subscriber disconnects, this address is released for other subscribers to use and subscribers will be given an address. in the new connection.
Static DNS system. & nbsp;
Every computer, network device (host) on the Internet is connected by IP address. For the convenience of using the name (domain name) to identify that host, Domain Name System is used to map the domain name to an IP address, so when you want to contact the host People use a memorable string (domain name), instead of using an IP address that is a long string of numbers.
When a user requests to declare a domain map to an IP address, there are two possible options:
- Require the server administrator to manage the domain name declared in the domain name
- Through the interface provides users with self-updating
However, with the above, it must be done by the labor factor, so it is not immediately reflected. However, it is very suitable for systems where IP addresses are less varied (leased-line systems).
With the services provided with dynamic IP address (dial-up, ADSL), each connection is assigned a different IP address, which is unknown where the dynamic domain and dynamic IP address mapping is. very difficult, unable to perform workers.
Using a static DNS service, subscribers of various types of connection services provided by ISPs that provide dynamic addresses such as dialup or ADSL can not maintain the service provider itself. For example, organizations rent high-speed ADSL lines, but improve the speed of Internet access. But if that organization wants to set up a website with registered domain name associated with the organization's transaction name www.AzSoft.com.vn and use email with registered domain name info@AzSoft.com.vn , the organization has to hire the ISP's mail hosting and web hosting service (ie install these services on the ISP's server) because the ISP's server has a direct Internet connection and a static IP address.
Therefore, Dynamic DNS was developed to provide domain name services for Internet-connected objects with dynamic IP addresses, with IP addresses of high-frequency hosts that can still maintain their own servers. service level.
Dynamic Domain Name System (Dynamic DNS).
In short, Dynamic DNS is the method of mapping domain names to highly variable IP addresses (because not all computers use static IP addresses). The Dynamic DNS service provides a special program that runs on the user's computer's dynamic DNS service called the Dynamic Dns Client. This program monitors the change of IP address at the host and contacts the DNS system whenever the host's IP address (which is provided by the ISP dynamically) changes and then updates the information to the base. DNS data about the change of address. This way, even if the server is frequently changed address, the domain is still the DNS server system pointing to the new IP address.
So who needs dynamic DNS:
As mentioned above, those who do not use a leased-line Internet connection service with a static IP address that rents an indirect dialup Internet connection or ADSL service has a dynamic IP address. Dynamic DNS can completely maintain its own server service.
In particular, fast growing number of ADSL subscribers will be very responsive to dynamic DNS service because with dynamic DNS, ADSL subscribers (usually organizations) have the ability to maintain their own mail servers. , web, ftp ... server, not renting mail hosting service, web hosting of ISP which is very expensive. Self-retaining servers were previously only available to leased-line direct connections, which are a form of high-cost connectivity.
To use dynamic DNS client services to do:
To use Dynamic DNS service ADSL customers only need to register service with VNNIC, VNNIC will grant domain name, account to authenticate. Customers then download the VNNIC Dynamic DNS Client program to install and set parameters (domain name, server name, account). This program will monitor and update the VNNIC DNS system when the IP change of the ADSL connection, ensuring the customer's domain name is always pointing.
Registered Address: http://dyndns.vnnic.net.vn
