Network Foundation II: IP Address

First, IP address

Iana

IANA refers to the organization (Internet Assigned Numbers Authority), the Internet number assignment. Responsible for IP address assignment planning and port definition for TCP/UDP public services.

IP address is a 32-bit binary number, usually divided into 4 "8-bit binary

IP addresses are usually expressed as "dotted decimal " in (a.b.c.d) Form, where a,b,c,d are decimal integers between 0~255.

Example: Point 10-in IP address (100.4.5.6), which is actually a 32-bit binary number (01100100.00000100.00000101.00000110).

the address format is :IP address = Network address + host address or IP address = host address + subnet address + host address.

IP Address Type
When the internetwork was originally designed for easy addressing and hierarchical construction of the network, each IP address consisted of two identification codes (IDS), the network ID and the host ID.

All hosts on the same physical network use the same network ID, and one host on the network (including workstations on the network, servers, routers, etc.) has a host ID corresponding to it. The IP address is divided into 5 types according to the network ID, Class A address, Class B address, Class C address, Class D address, and Class E address.

Big: 0 0000-0 111 1111 0-127 A

Medium: Ten 0000-10 1111 128-191 B

Small: 0 0000-110 1 1111 192-223 C

1110 0000-1110 11111 224-239

1111 0000-1111 1111 240-255

The first set of numbers for Class A addresses is 1~126. Note that the numbers 0 and 127 are not used as Class A addresses, the number 127 is reserved for the internal loopback function, and the number 0 indicates that the address is a local host and cannot be transmitted.
The first set of numbers for Class B addresses is 128~191.
The first set of numbers for Class C addresses is 192~223.

Host bit all 0: network address

Host bit full 1: Broadcast address

a:1-126

2^7-2 a network

Hosts per network: 2^24-2

b:128-191

2^14 a network

Hosts in each network: 2^16-2

c:192-223

2^21 a network

Hosts in each network: 2^8-2

1. Class A IP address  
        A Class A IP address consists of 1 bytes of network address and 3-byte host address, The highest bit of the network address must be "0" , the address range is from 1.0.0.0 to 126.0.0.0, the default netmask is: 255.0.0.0; There are 126 available Class A networks, and each network can hold more than 100 million hosts. &NBSP,
2. Class B IP address  
      A class B IP address consists of 2-byte network address and 2-byte host address, The highest bit of the network address must be "ten" , the address range is from 128.0.0.0 to 191.255.255.255, the default netmask is: 255.255.0.0; The available class B networks are 16,382 and each network can hold more than 60,000 hosts.  

3. Class C IP address  
      A class C IP address consists of 3 bytes of network address and 1 bytes of host address, The highest bit of the network address must be "" ". range from 192.0.0.0 to 223.255.255.255, the default netmask is: 255.255.255.0;c class network can reach more than 2.09 million, each network can accommodate 254 hosts. &NBSP,
4. Class D addresses are used for multipoint broadcasts (multicast).  
    class-D IP address the first byte begins with "1110", which is a specially reserved address. It does not point to a particular network, which is currently used in multipoint broadcasts (multicast). Multicast addresses are used to address a group of computers at a time, identifying a group of computers that share the same protocol. &NBSP,
5. Class E IP address  
      start with "11110" and use reservations for the future.  
all 0 ("0. 0. 0. 0 ") address corresponds to the current host. Full "1" IP address ("255". 255. 255. 255 ") is the broadcast address of the current subnet.

Read Baidu know some of the statements are as follows:

1. Strictly speaking, 0.0.0.0 is not a real IP address. It represents such a collection: all unclear hosts and destination networks. The "unclear" here means that there is no specific entry in the local routing table to indicate how to get there. For this machine, it is a "shelter", all do not know the "three No" personnel, are sent in. If you set a default gateway in your network settings, the Windows system automatically generates a default route with the destination address of 0.0.0.0.

2. the IP address of the 0.0.0.0 in the network represents the entire network , that is, all hosts in the network.

Its purpose is to help the router send packets that cannot be queried in the routing table . If you set a route for all 0 networks, packets that cannot be queried in the routing table will be routed to all 0 networks.

0.0.0.0 means listening for all local IP addresses, other computers are accessible, and modifying IP is not ringing. 127.0.0.1 indicates that only the native loopback address is being monitored and can only be accessed natively. x.x.x.x IP address, is only listening to this IP. The program will not be able to listen after modifying the IP. Need to manually modify the software listening address to use localhost only 127.0.0.1 alias

of the 3 main types of IP addresses, 3 zones are reserved as private addresses, with the following ranges of addresses:  

Class A address: 10.0.0.0~10.255.255.255 of 1

Class B Address:172.16.0.0~172.31.255.255 16
Class C Address:192.168.0.0~192.168.255.255 256

Subnets and hyper-nets:

Routing table:

Static settings

Dynamic Generation: Announcements

Direct-attached networks:

Network to which the next hop arrives:

Cost: Costs

The fewer hops you pass, the smaller the number.

Duration

Routing protocol: RIP2,OSPF,EIGRP, learning to generate a routing table,

routable protocol: IP protocol

Ports: For marking processes, 0-65535

IP: Host-to-host addressing

Default route, Gateway

Protocol stack: Kernel

TCP/IP protocol cluster

Host name : FQDN (full qulified Domain)

        Fully qualified domain name, refers to the hostname plus full path ,.

The domain name can be logically and accurately represent where the host is, or it can be said that the full domain name is a complete representation of the host name .

From the information contained in the full domain name, you can see the location of the host in the domain tree.

DNS resolution process: First find the native hosts table, and some directly use the table definition, no lookup network connections set in the DNS server by him to parse.

Www.magedu.com

Network Foundation II: IP Address