Reserved IP address Daquan

Source: Internet
Author: User

The IP address is a 32-bit binary array and is unique in the Internet. In order to facilitate the Administrator's arrangement of the Intranet, some special IP addresses reserved are not allocated on the Internet. Next let's take a look at the role of these IP addresses.

1. 127.0.0.1
127 is a reserved address, which refers to the computer itself. It is reserved for testing and used for testing network software and communication between local processes. In a Windows system, the address also has the name "localhost", no matter whichProgramOnce data is sent using this address, the protocol software will return immediately without any network transmission. Unless an error occurs, groups containing this network number cannot appear on any network.

2. 10. *, 172. 16. *. *-172. 31. *. *, 192. 168 .*.*
The preceding three CIDR blocks are private addresses that can be used for self-built networking. These addresses are mainly used in internal enterprise networks, but cannot be used on the Internet, to access the Internet, computers using these three network segments must translate private addresses into public IP addresses through address translation (NAT. Some bandwidth routers or other network devices usually use 192.168.1.1 as the default address. Because the private personal network is not interconnected with the external network, you can use random IP addresses, retain the IP addresses of these three CIDR blocks for use to avoid address confusion when accessing the public network in the future.

Iii. 0.0.0.0
Strictly speaking, 0.0.0.0 is no longer a real IP address. It represents a set of unknown hosts and destination networks. It is unclear that no specific entries in the route table of the Local Machine indicate how to arrive. For the local machine, it is a shelter, and all three people who do not know will be sent in. If you set the default gateway in the network settings, the Windows system will automatically generate a default route with the destination address 0.0.0.0.

Iv. 255.255.255.255
The restricted broadcast address. For the local machine, this address refers to all hosts in this segment (the same broadcast domain). This address is used for the destination address of IP packets during host configuration, at this time, the host may not know the network mask of its network, or even its IP address. Under any circumstances, the router prohibits the forwarding of packets whose destination address is a restricted broadcast address. Such packets only appear in the ingress network.

V. 224.0.0.0-239.255.255.255
This is a multicast address. Pay attention to its difference from the broadcast address. Specifically, 224.0.0.1 refers to all hosts, 224.0.0.2 refers to all routers, and 224.0.0.5 refers to all OSPF router addresses, 224.0.0.13 refers to the address of the pimv2 router. In addition, vrouters from 224.0.0.0-224.0.0.255 can only be used in the LAN and will not be forwarded. 239.0.0.0-239.255.255.255 is a private address (with 192.168. *. * functions are the same.) 224.0.1.0-238.255.255.255 can be used on the Internet. If IRDP is enabled on your host
Discover the protocol and use the multicast function), so your host routing table should have such a route.

Vi. 169. 254 .*.*
If your host uses the DHCP function to automatically obtain an IP address, when your DHCP server fails or the response time is too long and exceeds the time specified by the system, the Windows system will assign you such an address. If you find that the IP address of your host is such an address, unfortunately, your network cannot run normally.

Reprinted: http://hi.baidu.com/mushiyuan1987/item/27383cf98d39736b3d148566

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.