Linux Network Configuration

IP Address -- in the Internet, each host that is connected to the network has a unique IP address. --TheIP address is a dotted-decimal structure that takes a 32-bit binary number using a period (.) Divided into four parts, then each part is converted into a decimal tree. --An IP address can uniquely represent a host on an Internet network . For example 192. 168.1. .

Subnet and subnet mask --The subnet mask is also a set of ". " a delimited 4-segment number that can be used to define the network to which an IP address belongs. -- The subnet mask that typically defines the standard A,B,C class IP address is:  Class A subnet mask:255.0.  0.0  Class B subnet Mask:255.255.  0.0  Class C subnet Mask:255.255.  255.0- subnet mask is to facilitate the router to determine the network of the host being accessed, the router will be the host's IP address and its subnet mask to do bit and operation (0), after the  bit and operation, If the host's bit and the result of the operation and the access to the host's bit and the results of the operation is consistent, it is stated that in the same network,  not in the same LAN, the need to send a request outside the network. --Different types of subnet masks determine the number of hosts in the LAN (the most Class A, the least class C)

Port -- The port can see the wrong attachment point of the network connection -- If an application wants to provide a service, it will be attached to a particular network port waiting for the arrival of the user's request (also known as the listener of the team port). A  client that uses the service establishes a connection to that remote host on a port

Domain name--using the host's IP address on the Internet to locate and identify the host, but the IP address is difficult to remember, in order to solve this problem, put forward the concept of network domain name. --The Internet domain name is a server on an Internet network or a network system.--all over the world, domain names are unique. In layman's words, the domain name is equivalent to each server or host alias. --a domain name is a hierarchy of names, consisting of several English letters and numbers,"."separated into several parts, the general domain name format is: Host name. Level three domain name. Level Two domain name--in fact, the IP network does not recognize the domain name, the IP network only recognizes the IP address, when the user enters the IP address directly, the router will directly send the request to the target host, but if the user enters the domain name, then the user's primary opportunity to first access the DNS server, The DNS server returns the IP address of the current domain name to the user host and then the user host accesses the target server through the IP address of the domain name.--Domain name example domain name infosec.aust.edu.cn a domain name in the information security Department of Anhui Polytechnic University-InfoSec reflects the information security Department of a server. -Aust is the domain name of Anhui Polytechnic University. -Edu is the Ministry of Education Domain-CN is the top-level domain name, representing China--top-level domains generally fall into two categories: organizational top-level domains (see table 1) and geographic top-level domains (see table 2). An organizational top-level domain is used to indicate the properties of a site, and a ground-level domain name is used to indicate which country or region the address of the site belongs to
--Organizational top-level domain names generally need to apply in the United States, the rational top-level domain can be applied in the region. 

Linux Network Configuration