Linux Network-related commands and linux Network-related commands

Linux Network-related commands and linux Network-related commands
Ifconfig

Ifconfig is the command to view the NIC in centos6. In centos7, you must install the net-tools package before using it?
Nic configuration file:/etc/sysconfig/network-scripts/ifcfg-ens33?
Command: ifconfig

[root@shuai-01 ~]# ifconfigens33: flags=4163
 
    mtu 1500        inet 192.168.176.135  netmask 255.255.255.0  broadcast 192.168.176.255        inet6 fe80::16f5:8ee4:b971:e6fb  prefixlen 64  scopeid 0x20
          ether 00:0c:29:a1:0e:2c  txqueuelen 1000  (Ethernet)        RX packets 236  bytes 23351 (22.8 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 216  bytes 25791 (25.1 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0lo: flags=73
  
     mtu 65536        inet 127.0.0.1  netmask 255.0.0.0        inet6 ::1  prefixlen 128  scopeid 0x10
   
            loop  txqueuelen 1  (Local Loopback)        RX packets 68  bytes 5524 (5.3 KiB)        RX errors 0  dropped 0  overruns 0  frame 0        TX packets 68  bytes 5524 (5.3 KiB)        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
   
  
 

Disable NIC:

ifdown ens33

Enable NIC:

ifup ens33

When the network card is disabled, it cannot be remotely connected. Especially when you are using this Nic.

To restart an Eni:

[Root @ shuai-01 ~] # Ifdown ens33 & ifup ens33 disconnect the device 'ens33 '. Successfully activated connections (D-Bus activation path:/org/freedesktop/NetworkManager/ActiveConnection/1)

To restart the network service:

service restrat network

Set multiple ip addresses for one network card

One Nic can have multiple IP addresses. How can I set a virtual IP address for one Nic?
Enter the NIC configuration file and copy a configuration file

[root@shuai-01 ~]# cd /etc/sysconfig/network-scripts/[root@shuai-01 network-scripts]# lsifcfg-ens33  ifdown-ppp       ifup-ib      ifup-Teamifcfg-lo     ifdown-routes    ifup-ippp    ifup-TeamPortifdown       ifdown-sit       ifup-ipv6    ifup-tunnelifdown-bnep  ifdown-Team      ifup-isdn    ifup-wirelessifdown-eth   ifdown-TeamPort  ifup-plip    init.ipv6-globalifdown-ib    ifdown-tunnel    ifup-plusb   network-functionsifdown-ippp  ifup             ifup-post    network-functions-ipv6ifdown-ipv6  ifup-aliases     ifup-pppifdown-isdn  ifup-bnep        ifup-routesifdown-post  ifup-eth         ifup-sit[root@shuai-01 network-scripts]# cp ifcfg-ens33 ifcfg-ens33:0

Vi new configuration file change information: NAME, DEVICE, IPADDR, GATEWAY, DNS

NAME=ens33:0DEVICE=ens33:0IPADDR=192.168.176.150

GATEWAY, DNS do not

Restart the NIC after saving and exiting:

[root@shuai-01 network-scripts]# ifdown ens33 && ifup ens33

View the connection status of the ENI

Command: mii-tool

[root@shuai-01 network-scripts]# mii-tool ens33ens33: negotiated 1000baseT-FD flow-control, link ok

Link OK indicates the connected network cable?
Command: ethtool

[root@shuai-01 network-scripts]# ethtool ens33Settings for ens33:    Supported ports: [ TP ]    Supported link modes:   10baseT/Half 10baseT/Full                             100baseT/Half 100baseT/Full                             1000baseT/Full     Supported pause frame use: No    Supports auto-negotiation: Yes    Advertised link modes:  10baseT/Half 10baseT/Full                             100baseT/Half 100baseT/Full                             1000baseT/Full     Advertised pause frame use: No    Advertised auto-negotiation: Yes    Speed: 1000Mb/s    Duplex: Full    Port: Twisted Pair    PHYAD: 0    Transceiver: internal    Auto-negotiation: on    MDI-X: off (auto)    Supports Wake-on: d    Wake-on: d    Current message level: 0x00000007 (7)                   drv probe link    Link detected: yes

Link detected: yes indicates the network connection.

Change Host Name

Command: hostnamectl?
Command Format: hostnamectl set-hostname Host Name

Host Name configuration file:/etc/hostname

Set dns

Dns configuration file:/etc/resolv. conf

View the dns configuration file:

[root@shuai-01 network-scripts]# cat /etc/resolv.conf # Generated by NetworkManagernameserver 119.29.29.29

Can I change the dns in the NIC configuration file or in the dns configuration file?
Add:

DNS2=8.8.8.8

In the dns configuration file (temporary ):

nameserver 8.8.8.8

The custom dns domain name takes effect on the local machine. After the definition, you do not need to enter the dns resolution domain name .?
Configuration File:/etc/hosts

Add a DNS domain name:

[root@shuai-01 network-scripts]# vim /etc/hosts

Add DNS domain name:

192.168.172.3 www.baidu.com193.168.176.56 www.qq.com www.hao123.com

Ping:

[root@shuai-01 network-scripts]# ping www.baidu.comPING www.baidu.com (192.168.172.3) 56(84) bytes of data.[root@shuai-01 network-scripts]# ping www.qq.comPING www.qq.com (193.168.176.56) 56(84) bytes of data.

• One IP address can be followed by multiple domain names
• One row can have only one IP Address