Linux Network Management--Basic command of network management

Linux mainly uses three types of network management commands: 1.ifconfig, route and Netstat belong to the traditional function of single-class network command; 2.ip and SS belong to the Integrated class Network command; The 3.NMCLI is suitable for comprehensive network commands in RHEL7, and can also be configured with a configuration file for network management.

This article mainly explains these three kinds of network Management command and the related configuration file.

Note: The network parameters modified by the command are lost after the network service restarts, and only the network parameters modified by the configuration file can be permanently valid.

1-1. ifconfig Command

Function: View or configure network interface parameters

Format:

Ifconfig [interface] [Up|down] view specified network interface parameters, set network interface status

Common options:

-A: Show all network interface information

-S: Display network interface statistics 650) this.width=650; "Src=" http://s3.51cto.com/wyfs02/M02/72/9F/wKioL1XpkHCjplYGAAIkgqmutNI847.jpg " Style= "Float:left;" title= "Network management--ifconfig01.jpg" alt= "Wkiol1xpkhcjplygaaikgqmutni847.jpg"/>

The default Ifconfig only displays the active network interface and does not disappear. Turn off network interface parameters

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ifconfig INT address Configure IP addresses for specified network interfaces

ifconfig int ip/mask or ifconfig int IP netmask MASK modifies the IP address of the specified device

# When configuring an IP address, if the mask uses dotted decimal notation, you must use the keyword network

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1-2. Route command

Role: View or configure a local routing entry

Format:

Route View Routing Entry

Options:

-N: Do not parse the domain name and display it with an IP address

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Route Add-net|-host|default TARGET [netmask MASK] [GW GW] [mertic N] [Dev INT]

Route del -net|-host|default TARGET [netmask MASK] [GW GW] [Dev INT]

Add or remove a route entry

Host route entry using keyword-host, network routing entry using keyword-network, default route entry using keyword default

Mertic N: Used to specify route entry metrics

Dev INT: Specify the Fight interface

Add host route entry Route Add-host 1.1.1.1 GW 10.10.10.1 metric Dev eth1

The next hop address is: 10.10.10.1, the route entry measure is 15, the outbound interface is eth1

Network routing entry route add-net 3.3.3.0/24 metric 7 Dev eth0

The measure value is 7 and the outbound interface is eth0

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To delete a network route entry

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1-3. Netstat command

Function: View the network properties of this computer by specifying options

Format: netstat [options]

Common options:

-N: Digital display of IP and ports

-T: Show TCP connections

-u: Show UDP connections

-L: In the Listening State port

-A: all States

-E: Extended format

-P: Show related processes and PID

-R: Show kernel routing table

-I INT: Displays statistics for the specified interface

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2-1. IP command

Function: Configure the Native interface status, network parameters and routing entries

Format: IP [OPTIONS] OBJECT {COMMAND | help}

when object is link , configure the two-Layer link property configured for the native

The corresponding command is:

IP link set DEVICE {up | | \ arp {on | off}: Set two-layer link interface status

IP link Show [device]: View device properties

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Used to set the native IP address when object is address

The corresponding command is:

IP Addr {add | del} ifaddr dev STRING: Add or remove IP addresses to the specified network interface

IP Addr {show | flush} [Dev STRING]: View or empty the IP address of the specified device

Add Ip/mask: Adding addresses to devices

Delete IP: Remove the address of the device configuration

Flush: Empties the configuration from the specified device

Show: View IP address configuration

Add a specified IP address via the add command

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Specify all IP addresses for the network interface through flush conditions

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Used to set the native route entry when object is a route

The corresponding command is:

IP route {list | flush} SELECTOR: View or empty route entry

IP route {Add | del | change | append | replace | monitor} route: Modify route entry

Add a route entry via the Add command

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To modify a route entry by using the change command

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2-2. SS command

Function: Specify options to display the local network parameters

# The SS command works the same as the Netstat command, but the execution is more efficient and the SS command is recommended when the system is busy

Format: SS [Options]

Common options:

-N: Digital display of IP and ports

-T: Show TCP connections

-u: Show UDP connections

-L: In the Listening State port

-A: all States

-E: Extended format

-P: Show related processes and PID

-R: Show kernel routing table

-I INT: Displays statistics for the specified interface

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3-1. NMCLI command

The NMCLI command is a command-line tool for managing NetworkManager in RHEL7, and Nmcli is a powerful, flexible command, but also very complex. This is only a brief introduction to NMCLI's connection and device two objects.

Role: Used to create, display, edit, delete, activate and deactivate network connections

Format: nmcli [OPTIONS] OBJECT {COMMAND | help}

# NMCLI supports tab completion for object and COMMAND input, is more user-friendly, and has a corresponding help option in all levels of object, which brings great convenience when used.

When object is connection ,

corresponding command: = {Show | up | down | add | edit | modify | delete | reload | load}

The main implementation of the local network connection status of the view, management and other operations

Management of local network connections via connection

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Various parameters of network connection can be modified by modify subcommand

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When object is a device ,

corresponding command: = {Status | show | connect | disconnect | delete | wifi | wimax}

For viewing and managing on-premises network interface devices

Detailed configuration information for network interfaces can be viewed through the SHOW subcommand

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4. Modifying network parameters through configuration files

4-1. IP address configuration file:/etc/sysconfig/network-scripts/ifcfg-int

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Field Explanation:

# Cat Ifcfg-eth0
Device= specifying the device name
bootproto= Specify IP Address acquisition method: DHCP or static
Hwaddr= specifying the hardware NIC MAC address
Nm_controlled= NM represents the NetworkManager script to replace the network protocol

Peerdns= indicates whether DNS received by the server is overwritten in the DNS configuration file if the IP address is obtained by DHCP

onboot= Specifies whether to start the network adapter device automatically
type= Display Network Interface type
Uuid= the UUID of the specified device
Ipv6init= whether the IPV6 feature is enabled
userctl= Specifies whether a normal user controls the device

Static IP addresses require the following fields to be configured:
Ipaddr= Specify IP Address
netmask= Subnet Mask
gateway= Default Gateway
dns#= DNS server address, 3 DNS server addresses can be configured at the same time, with higher priority than DNS configuration in/etc/resilov.conf

4-2. Routing configuration file:/etc/sysconfig/network-scripts/route-int

# Configuration files need to be created manually

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File format

1. Single Statement format

TARGET via GW

Ex:192.168.50.128/28 via 10.10.10.11

2. Define one route per three lines

Address#=target

Netmask#=mask

Gateway#=gw

EX:

address0=192.168.50.128

netmask0=255.255.255.224

gateway0=10.10.10.11

# only one format can be used in the same file

4-3. DNS configuration file:/etc/resolove.conf

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To specify a DNS server by nameserver dns_ip

I have limited level, if there is improper understanding of the place, please give correct, thank you very much!

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Linux Network Management--Basic command of network management