LINUX network settings

catalogue

View network configuration

Test network connection

Using the network configuration command

Modify network profile

summary

View network configuration

View network interface information ifconfig

View host name hostname

View the route table entry route

View network connectivity netstat

Get socket statistics ss

Test network connection

Test network connection ping

Trace packet traceroute

Domain name resolution nslookup

Using the network configuration command

How to set network parameters

Set network interface parameter ifconfig

Set route record

Modify hostname hostname

Modify network profile

Network interface profile

Network interface profile

Enable and disable network interface configuration

Domain name resolution profile

Local host mapping file

summary

View network configuration

Maximum mtu packet transfer rate

View network interface information ifconfig

  • View all active network interface information

    • Execute ifconfig command

  • View specified network interface information

ifconfig network interface

[root@localhost ~]# ifconfig ens33
ens33 flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.4.11 netmask 255.255.255.0 broadcast 192.168.4.255
inet6 fe80.9106:d38b:670d:1a89 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:3a:81:cc txqueuelen 1000(Ethernet)
..//Omit some contents

View host name hostname

  • hostname command

    • View or set the current hostname

Hostname [hostname] (temporary)

  • Example

[root@localhost ~]# hostname
localhost.localdomain

View the route table entry route

route command

View or set routing table information in the host

route [-n]

Example

[root@localhost ~]# route -n
Kernel IP routing table
Destination     Gateway      Genmask       Flags    Metric    Ref    Use    lface
0.0.0.0       192.168.4.1    0.0.0.0        UG       100       0      0     ens33
192.168.4.0    0.0.0.0    255.255.255.0     U        100       0      0     ens33

View network connectivity netstat

  • netstat command

    • View the network connection status, routing table, interface statistics and other information of the system

netstat [options]

  • Common options

    • -a,-n,-p,-t,-u,-r

[root@localhost~]# netstat -anpt | grep ":80"
tcp60   0  :::80  :::*  LISTEN  20563/httpd

Get socket statistics ss

  • ss command

    • Check the network connection of the system and obtain socket statistics

ss [options]

  • Common options

    • -t,-u,-n,-l,-p,-a,-r

[root@localhost ~]# ss -t state established
Recv-Q  Send-Q   Local Address:Port   Peer Address:Port
0       96       192.168.8.10:ssh     192.168.8.1:55213

Test network connection

Test network connection ping

  • ping command

    • Test network connectivity

ping [options] target host

  • Example

[root@localhost ~]# ping 192.168.4.110
PING 192.168.4.110 (192.168.4.110)56(84) bytes of data.
64 bytes from 192.168.4.110: icmp_seq=2 ttl=128 time=0.274 ms
^C  Press Ctrl+C abort test 
---192.168.4.110 ping statistics---
2 packets transmitted, 2 received,0% packet loss, time 1162ms
rtt min/avg/max/mdev = 0.274/0.484/0.694/0.210 ms

Trace packet traceroute

  • traceroute command

    • Test the network nodes passing from the current host to the destination host

traceroute destination host address

  • Example

[root@localhost ~]# traceroute 192.168.7.7
traceroute to 192.168.7.7 (192.168.7.7),30 hops max, 40 byte packets
1 (192.168.4.1)7.740 ms 15.581 ms 15.881 ms
2 (192.168.7.7)19.652 ms 19.995 ms 19.942 ms

Domain name resolution nslookup

  • nslookup command

    • Test DNS domain name resolution

nslookup destination host address [DNS server address]

  • Example

[root@localhost ~]# nslookup www.google.com
Server:  202.106.0.20     DNS server address
Address: 202.106.0.20#53
Non-authoritative answer:
Name: www.l.google.com    Analytic IP address
Address:173.194.127.51

Using the network configuration command

How to set network parameters

  • Temporary configuration - use commands to adjust network parameters

    • It is simple and fast, and can directly modify the network parameters in operation

    • Generally, it is only suitable for use in the process of debugging the network

    • After the system is restarted, the modifications will be invalid

  • Fixed settings - modify network parameters through the configuration file

    • Modify the configuration file of various network parameters

    • It is suitable for setting fixed parameters on the server

    • It will not take effect until the network service is overloaded or restarted

Set network interface parameter ifconfig

  • Set the IP address and subnet mask of the network interface

ifconfig network interface ip address [netmask]
ifconfig network interface ip address [/ subnet mask length]

  • Disable or reactivate the network card

ifconfig network interface up 
ifconfig network interface down

  • Set virtual network interface

ifconfig network interface: serial number IP address

Set route record

  • The routing record added to the specified network segment

route add -net segment address gw IP address

  • Delete the routing record to the specified network segment

route del -net segment address

  • Adds a default gateway record to the routing table

route add default gw IP address

  • Delete the default gateway record in the routing table

route del default gw IP address

Modify hostname hostname

  • hostname command

    • Set host name

hostname host name

Example

[root@localhost ~]# hostnamelocalhost.localdomain
[root@localhost ~]# hostname www.bdqncom
[root@localhost ~]# hostname
www.bdqn.com
[root@localhost ~]# bash enables a new Shell session
[root@www ~]#

Modify network profile

Network interface profile

  • /Under / etc / sysconfig / network scripts /

    • ifcfg-ens33: configuration file of the first Ethernet card

[root@localhost ~]# ls /etc/sysconfig/network-scripts/ifcfg-*
/etc/sysconfig/network-scripts/ifcfg-ens33
/etc/sysconfig/network-scripts/ifcfg-lo

Network interface profile

  • /Under / etc / sysconfig / network scripts /

    • ifcfg-ens33: configuration file of the first Ethernet card

[root@localhost ~]# vim /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet
BOOTPROTO=static
DEVICE=ens33
ONBOOT=yes
IPADDR=192.168.4.11
NETMASK=255.255.255.0
GATEWAY=192.168.4.100

Enable and disable network interface configuration

  • Restart network service

[root@localhost ~]# systemctl restart network

  • Disable and enable network interface

[root@localhost ~]# ifdown ens33
[root@localhost ~]# ifup ens33

Domain name resolution profile

  • /etc/resolv.conf file

    • Save the IP address of the DNS server that this machine needs to use

[root@localhost ~]# vi /etc/resolv.conf
search localdomain
nameserver 202.106.0.20
nameserver 202.106.148.1

Note: CentOS 7 needs to be installed in NetworkManager Set dns=none in the main section of the conf file and restart the NetworkManager service, or use the nmcti command newly added by CentOS7 to set it

Local host mapping file

  • /etc/hosts file

    • Save the mapping record of host name and IP address

[root@localhost ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.
119.75.218.70 www.baidu.com

  • Comparison between hosts file and DNS server

    • By default, the system first looks for the parsing record from the hosts file

    • The hosts file is only valid for the current host

    • The hosts file can reduce the DNS query process and speed up access

summary

  • View network configuration

    • ifconfig,hostname,route,netstat,ss

  • Test network connection

    • ping,traceroute,nslookup,dig

  • Set network address parameters

    • Temporary configuration, permanent configuration

Keywords: Linux network server

Added by ClaytonBellmor on Sun, 16 Jan 2022 17:12:39 +0200

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