1. Connect a Linux host to the network and need to configure network-related settings
Generally includes:
Host Name
Ip/netmask
Routing: Default gateway
DNS Server
Primary DNS Server
Secondary DNS server
Second time DNS server
2. Static designation:
Ifcfg:ifconfig,route,netstat
Ip:object{link,addr,route},ss,tc
System-config-network-tui (Setup)
Configuration file
Centos 7: Network Configuration Tool
Nmcli,nmtui,nm-connection-editor
Dynamic allocation:
Dhcp:dynamic Host Configuration Protocol
Ifconfig
Ifconfig-a
Ifconfig eth0 (Up|down)
Ifconfig eth0 Ip/netmask [Up|down]
#立即生效
Route command:
View routes: Route-n
Add route: Route add
Route add [-net|-host] target [netmask Nm] [GW Gw][[dev] If]
Target: 10.1.249.112 Gateway: 10.1.0.1
[Email protected]]# Route add-host 10.1.249.112 GW 10.1.0.1 Dev eth0
Target: 10.1.249.0 Gateway: 10.1.0.1
[Email protected]]# Route add-net 10.1.249.0 netmask 255.255.0.0 gw 10.1.0.1 Dev eth0
[Email protected]]# Route add-net 10.1.249.0/16 GW 10.1.0.1 Dev eth0
Default Route Gateway 10.1.0.1
[Email protected]]# Route add-net 0.0.0.0 netmask 0.0.0.0 GW 10.1.0.1
[[email protected]]# route add default GW 10.1.0.1
Delete target: 10.1.249.112 Gateway: 10.1.0.1
[Email protected]]# Route del host 10.1.249.112
Delete target: 10.1.249.0 Gateway: 10.1.0.1
[Email protected]]# Route del-net 10.1.249.0 netmask 255.255.0.0
Netstat command:
Netstat-print network connections,routing tables,interface statistics,masquerade Connections,and Multicast Memberships
Show Network Connections:
netstat [--tcp|-t] [--udp|-u] [--raw|-w] [--listening|-l] [--all|-a] [--NUMERIC|-N][--EXTEND|-E] [--program|-p]
-T:TCP protocol Related
-U:UCP protocol Related
-w:raw Socket Related
-L: In listening state
-A: all States
-N: Digital display of IP and ports
-E: Extended format
-P: Show related processes and PID
Netstat common groups and:
-tan TCP protocol related, all States, with digital display IP and port
-uan UCP Protocol related, all States, to digitally display IP and ports
-TNL TCP protocol related to digital display IP and port, in listening state
-UNL UCP protocol related, digital display IP and port, in listening state
Display Interface Statistics:
Netstat-i displaying all interface data
Netstat-i=eth0 Display Eth0 Interface data
Ifconfig-s eth0 display Eth0 interface data
To set the IP command:
Ifup eth0 Open eth0 Port
Ifdown eth0 Close Eth0 Port
Set Temporary IP:
IP addr Add 10.1.249.111/16 dev eth0 label eth0:0
To delete a temporary IP:
IP addr del 10.1.249.111/16 dev eth0 label eth0:0
IP addr Flush Dev eth0 label eth0:0
SS Command:
Netstat to get socket information by traversing proc, SS uses NetLink to communicate with kernel Tcp_diag module to get socket information
Options:
-T TCP protocol related
-U UDP Protocol Related
-W Bare Socket related
-X UNIX Sock related
-L Listen Status link
-A All
-N Number format
-P related programs and PID
-E Extended Information
-M memory usage
-O Timer Information
Common combinations:
-tan TCP protocol related, all, number formats
-TANL TCP protocol related, all, number formats, listen status links
-TANLP TCP protocol related, all, number formats, listen status links related programs and PID
-uan UCP protocol related, all, numeric format
Common usage:
Ss-l Show all ports that are open locally
SS-PL Show each process specific open socket
Ss-t-A displays all TCP sockets
Ss-u-a show all UCP sockets
SS-S List Current Socket details
Ss-o State established ' (Dport =: ssh or sport =: SSH) ' Show all established SSH links
Ss-o State established ' (Dport =: http or sport =: http) ' Displays all established HTTP links
TCP Common Status:
TCP Finite state machine:
LISTEN: Monitoring
Established: Established links
Fin_wait_1: Waiting for a remote TCP link interrupt request, or confirmation of a previous link interrupt request
Fin_wait_2: Waiting for link interrupt request from remote TCP
Close-wait: Waiting for a link to be sent from a local user to interrupt the request
CLOSING: Waiting for remote TCP to confirm the link interruption
Last-ack: Wait for the original send to remote TCP link Interrupt Request Confirmation
Time-wait: Wait enough time to ensure that the remote TCP receives a link interrupt request acknowledgement
Syn-sent: Client syn_sent status
SYN-RECV: After the server has been passively opened, the client's SYN is received and the ACK state is sent.
Syn-received: Server-side status SYN_RCVD if you find that there are many SYN_RCVD states, your machine may be attacked by a SYN flood DOS (Denial of service attack)
CLOSEDSS: No connection status
3. Network configuration file
Onboot: Whether this device is activated at system boot time
Type: interface types; common Ethernet, Bridge.
UUID: Unique identification of the device
IPADDR: Specify IP Address
NETMASK: Subnet Mask
Gateway: Default Gateways
DNS1: The first DNS server points to a
DNS2: The second DNS server points to a
Userctl: Whether a normal user can control this device
Peerdns: If the value of Bootproto is "DHCP", does it allow
DHCP server-assigned DNS servers point to information that is directly overwritten in the/etc/resolv.conf file
Nic configuration file/etc/sysconfig/network-scripts
The parser performs forward and reverse queries:
/etc/hosts
Image of the local host name database and IP address
Useful for small standalone networks
Typically, before using DNS check, Getent hosts view/etc/hosts content
4. Network Card related commands:
Network interface identifies and names the associated udev configuration file
/etc/udev/rules.d/70-persistent-net.rules
To view the network card:
DMESG |grep–i ETH
Ethtool-i eth0
To uninstall the NIC driver:
Modprobe-r e1000
Rmmod e1000
Load NIC driver:
Modprobe e1000
5. Use traditional naming methods:
(1) Edit/etc/default/grub configuration file grub_cmdline_linux= "RHGB quiet net.ifnames=0" or: Modify/boot/grub2/grub.cfg
(2) generate its configuration file for Grub2 grub2-mkconfig-o/etc/grub2.cfg
(3) Rebooting the system
This article is from the "Linux Learning path" blog, so be sure to keep this source http://luyubo.blog.51cto.com/7634254/1847180
Linux Basic network Management