linux--Network Configuration (IFCFG)

What configuration items do I need to configure to access the Linux host to the network?

Ip/netmask: Local communication.

Routing (Network Management): cross-network communication.

DNS server address: Host-name-based communication.

There are three types of DNS servers: primary/Standby DNS server/third backup DNS server.

　　　The DNS server specifies that the configuration file needs to be modified/etc/resolv.conf

Hostname configuration: Modify/etc/sysconfig/network. CENTOS7 can be modified using the HOSTNAMECTL command.

　　　　　　Hostname command:

View: hostname

Configuration: hostname hostname. Invalid after temporary effective restart.

Hostnamectl Command (CENTOS7):

Hostnamectl Status: Displays the current hostname information

Hostnamectl set-hostname: Sets the hostname, permanently valid.

Configuration file:/etc/sysconfig/network

Hostname=

Configuration mode: Static assignment, dynamic acquisition.

Static designations are primarily used with the Ifcfg Family command, and the Iproute2 command.

Ifcfg

Ifconfig: Configuring IP and Netmask

Route: Configure Routing

Netstat: status and Statistics view

Iproute2:

IP OBJECT:

Addr: Address and mask

Link: interface

Route: Routing

SS: Status and Statistics view

Network configuration command on CENTOS7: NM (Networks Manage)

NMCLI: command-line tools

Nmtui:text Windows Tools

IFCFG Family command Detailed: Ifconfig,route,netstat

Ifconfig command: interface and address view and management. Functions are equivalent to IP addr and IP link in iproute2.

Ifconfig [INTERFACE]

Ifconfig: Default does not follow the parameter, only the interface that shows the activation state.

Ifconfig-a: Displays interfaces for all interfaces, including the inactive state.

Ifconfig interface [Aftype] options | Address

　　　　　　

Options:

Up: Enable interface

Down: The interface is closed, IP and mask cannot be omitted when used.

　　　　　　

Add: For adding an IPV6 address.

Del: Used to delete an IPV6 address.

Route command:

View:

Route-n

Add to:

Route add [-net|host] target [netmask Nm] [GW GW] [[Dev] If]

-net: Network Routing

-host: Host Routing

Target: Destination Address

Netmask Nm: Subnet mask for destination address

GW GW: Gateways

　　　　　　

Add a default route: Route add default GW 192.168.3.254

　　　　　　

　　　　　　　　

Delete:

Route del [-net|-host] target [netmask Nm] [GW GW]

　　　　　　

Delete default route: Route del Default

Netstat command:

Print network connections,routing tables,interface statistics,masquerade connections,and Multicast memberships (Printing Internet connection , routing tables, interface statistics, spoofing connections, and multicast members)

Show routing table: Netstat-r n

-R: Show kernel routing table

-N: Number format

Show Network Connections:

netstat [--tcp|-t] [--udp|-u] [--udplite|-u] [--sctp|-s] [--raw|-w] [--listening|-l] [--all|-a] [--numeric|-n] [-- EXTEND|-E] [--program|-p]

-T:TCP protocol-related connections. TCP is connected by a state.

-U:UDP related connections. Stateless connection.

-w:raw socket-related connections.

-L: The connection is in the listening state.

-A: All state connections.

-N: Displays IP and port in numeric format.

-P: Show related processes and PID

-E: Extended format displays details

Supplemental: TCP is a connection-oriented protocol that establishes a virtual link before the communication begins and the UI is removed after the communication is complete. The DUP has no connection protocol and sends data messages directly.

Display statistics for the interface:

netstat {--interface |-i |-i} [iface] [--all |-a] [--extend |-e] [--verbose |-v] [--program |-P] [--numeric | -N]

All interfaces:

Netstat-i

Specify the interface:

Netstat-i<iface>

　　　　　　　　

linux--Network Configuration (IFCFG)