Shulou(Shulou.com)06/01 Report--

I. Network configuration commands:

1. Ifconfig (configure network interface command)

Command format: ifconfig [interface]

Ifconfig interface [aftype] options | address...

Examples of commands:

# View the configuration information of all Nic interfaces: ifconfig [- a]

~] # ifconfig

# View the interface configuration information of a network card: ifconfig IFACE

~] # ifconfig eth0

# enable or disable an ENI interface: ifconfig IFACE [up | down]

~] # ifconfig eth0 down

# configure the IP address of the Nic interface:

Ifconfig IFACE IP/mask [up] / ifconfig IFACE IP netmask MASK

~] # ifconfig eth0:0 1.1.1.1 Compact 32 up

# enable or disable Nic promiscuous mode: ifconfig IFACE [-] promisc

~] # ifconfig eth0-promisc # disabled

2. Route (routing management command)

Command format: route [- CFvnee]

Route add/del [- net |-host] target [netmask Nm] [gw Gw] [metric N] [[dev] If]

Command usage:

# View:

~] # route-n

# add:

~] # route add-host 192.168.1.3 gw 172.16.0.1 dev eth0 # Host Route ~] # route add-net 192.168.0.0 netmask 255.255.255.0 gw 172.16.0.1 dev eth0 # Segment Route ~] # route add-net 192.168.0.0and24 gw 172.16.0.1 dev eth0 # Segment Route ~] # route add default gw 172.16.0.1 # default Route

# Delete:

~] # route del dev eth0 ~] # route del-host 192.168.1.3 ~] # route del-net 192.168.0.0 netmask 255.255.255.0

3. Specify the DNS server

Configuration file: / etc/resolv.conf

Add:

Nameserver DNS_SERVER_IP1

Nameserver DNS_SERVER_IP2

Nameserver DNS_SERVER_IP3

4. Netstat (network connection status display command)

Command format: netstat [OPTION]

Option:-t: related to tcp protocol

-u: related to udp protocol

-w: raw socket related

-l: in monitoring state

-a: all statu

-n: display IP and port in numbers

-e: extended format (display User and Inode)

-p: displays related processes and PID

Common combinations:

-tan.-uan.-tnl.-unl.

Display the routing table:

Netstat {--route |-r} [--numeric |-n]

-r: displays the kernel routing table (display)

-n: numeric format

-e: extended format (display Metric)

Display interface statistics:

Netstat {--interfaces |-I |-I} [iface] [--all |-a] [--extend |-e]

[--program |-p] [--numeric |-n]

# display statistics for all interfaces: netstat-I

~] # netstat-I

# display statistics for a specific interface: netstat-IIFACE

~] # netstat-Ieth0

Common status of TCP:

LISTEN: monitoring

ESTABLISHED: established connection

FIN_WAIT_1: active shutdown. A shutdown request has been issued, waiting for confirmation.

FIN_WAIT_2: active shutdown. You have received confirmation from the other party to close the transmission connection, waiting for the other party to send a request to close the connection.

SYN_SENT: send a SYN request and wait for the other party to confirm

SYN_RECV: a transfer request has been received but has not been confirmed yet

CLOSED: connection closed statu

5. Ss (network connection status display command, similar to netstat, more flexible and faster)

Format: ss [OPTION]... [FILTER]

Options:

-t: related to tcp protocol

-u: related to udp protocol

-w: bare socket related

-x:unix sock related

-l: connection with listen statu

-a: all

-n: numeric format

-p: related programs and PID

-e: extended information

-m: memory usage

-o: timer information

FILTER: = [state TCP-STATE] [EXPRESSION]

EXPRESSION:

Dport =

Sport =

~] # ss-o state established'(dport =: ssh or sport =: ssh)'

Common combinations:

-tan.-tanl.-tanlp.-uan.

Second, configure Linux network properties: ip command

Command format: ip [OPTIONS] OBJECT {COMMAND | help}

OBJECT: = {link | addr | route}

Link: network device attribute management

# display API attributes: ip link show [DEVICE] [up | down]

~] # ip link show eth0 ~] # ip link show up # shows the active interface

# set API attributes:

Ip link set DEVICE [{up | down} | [mtu MTU] | [promisc {on | off}]]

~] # ip link set eth0 up mtu 1500 promisc on

Addr:IP address management

Ip addr {add | del} IFADDR dev STRING

IFADDR available options:

[label LABEL]: indicates the alias of the network card when adding an address

[scope {global | link | host}]: indicates the scope (global: available globally, link: available only for links; host: available locally)

[broadcast ADDRESS]: indicates the broadcast address

# add IP

~] # ip addr add label eth0:0 2.2.2.2 Compact 24 dev eth0

# Delete IP

~] # ip addr del label eth0:0 2.2.2.2 Compact 24 dev eth0

Ip addr {show | flush} [dev DEVICE] [label PATTERN] [primary and secondary]

# display specified device IP information

~] # ip addr show label eth0:0 dev eth0 # displays IP information of Nic device aliases

# clear the IP information of the specified device

~] # ip addr show label eth0:0 dev eth0

Route: route management

Ip route {add | del | change} TARGET via GW dev IFACE src SOURCE_IP

TARGET: host routing: IP; Network routing: NETWORK/MASK

# add Host Route

~] # ip route 1.1.1.1 via 192.168.52.2 dev eth0

# add IP address range routing

~] # ip route add 2.2.2.0 dev eth0 src 24 via 192.168.52.2 dev eth0 src 192.168.52.20 # src specify the source IP

# add Gateway

~] # ip route add default via GW dev IFACE

# deleting a route:

~] # ip route del 1.1.1.1 via 192.168.52.2 dev eth0

# display routing information: ip route show

# clear the route list of specified devices: ip route flush dev IFACE

III. Linux network attribute configuration: modify the configuration file

IP, MASK, GW, DNS related configuration files:

/ etc/sysconfig/network-scripts/ifcfg-IFACE

Routing-related configuration files:

/ etc/sysconfig/network-scripts/route-IFACE

1. Set the interface parameters of the network card

/ etc/sysconfig/network-scripts/ifcfg-IFACE:

DEVICE: the device to which this profile is applied

HWADDR: the MAC address of the corresponding device

BOOTPROTO: address configuration protocol used to activate this device, commonly used dhcp, static, none, bootp

NM_CONTROLLED:NM is the abbreviation of NetworkManager; whether this Nic is controlled by NM; CentOS6 is recommended as "no"

ONBOOT: whether to activate this device when the system boots

TYPE: interface type; common Ethernet, Bridge

UUID: unique identification of the device

IPADDR: indicates the IP address

NETMASK: subnet mask

GATEWAY: default gateway

DNS1: the first DNS server points to

DNS2: the second DNS server points to

USERCTL: whether the average user can control this device

PEERDNS: if the value of BOOTPROTO is "dhcp", whether to allow the dns server assigned by dhcp server to point to information to directly override

To / etc/resolv.conf file

2. Define routes in the configuration file

Configuration file: / etc/sysconfig/network-scripts/route-IFACE

Two styles:

(1) TARGET via GW

(2) define one route every three lines

ADDRESS#=TARGET

NETMASK#=mask

GATEWAY#=GW

3. Configure the network card with multiple addresses:

(1) ifconfig: ifconfig IFACE_ALIAS

(2) ip:ip addr add

(3) configuration file: ifcfg-IFACE_ALIAS

DEVICE=IFACE_ALIAS

Note: gateway aliases cannot be booted using dhcp protocol

4. Tui (text user interface) configured with Linux network attributes

Command: system-config-network-tui or setup

Note: remember to restart the network service to take effect

5. Configure the hostname of the current host

Temporary effect: hostname [HOSTNAME]

Permanently effective: / etc/sysconfig/network

Add: HOSTNAME= your hostname

6. The network interface identifies and names the relevant udev configuration files:

/ etc/udev/rules.d/70-persistent-net.rules

Uninstall the Nic driver: modprobe-r e1000

Load the network card driver: modprobe E1000

IV. CentOS 7 network attribute configuration

(1) Nic naming mechanism

How systemd names network devices:

(a) if the index information provided by Firmware or BIOS for devices integrated on the motherboard is available and predictable, it is named after this index, such as eno1

(B) if the index information provided by Firmware or BIOS for the PCI-E expansion slot is available and predictable, name it according to this index, such as ens1

(C) if physical location information for the hardware interface is available, name it based on this information, such as enp2s0

(d) if the user starts it explicitly, it can also be named after the MAC address, enx2387a1dc56

(e) if none of the above is available, the traditional naming mechanism is used.

Some of the above naming mechanisms require the participation of biosdevname programs.

(2) the format of name composition

En: ethernet

Wl: wlan

Ww: wwan

Name type:

O: the device index number of the integrated device

S: the index number of the expansion slot

X: naming based on MAC address

Ps: enp2s1

(3) naming process of network card devices:

Step one:

Udev, accessibility program / lib/udev/rename_device, / usr/lib/udev/rules.d/60-net.rules

Step 2:

Biosdevname will be based on / usr/lib/udev/rules.d/71-biosdevname.rules

Step 3:

By detecting the network interface device, according to / usr/lib/udev/rules.d/75-net-description

ID_NET_NAME_ONBOARD, ID_NET_NAME_SLOT, ID_NET_NAME_PATH

Return to the traditional naming method:

Step one:

Edit / etc/default/grub configuration file

GRUB_CMDLINE_LINUX= "net.ifnames=0 rhgb quiet"

Step 2:

Generate its configuration file for grub2

Grub2-mkconfig-o / etc/grub2.cfg

Step 3:

Restart the system

(4) address configuration tool: nmcli

Nmcli [OPTIONS] OBJECT {COMMAND | help}

How to modify attributes such as IP address:

Usage: nmcli connection modify IFACE [+ | -] setting.property value

Setting.property:

Ipv4.addresses

Ipv4.gateway

Ipv4.dns1

Ipv4.method

# modify IP: [root@centos7 ~] # nmcli con modify eth0 ipv4.addresses 192.168.52.7 nmcli con modify eth0 24 # add IP: [root @ centos7 ~] # nmcli con modify eth0 + ipv4.addresses 1.1.1.1 IP: [root@centos7 ~] # nmcli con modify eth0-ipv4.addresses 1.1.1.1 IP: [root@centos7 ~] # nmcli con modify eth0 ipv4.gateway 192.168.52.modify DNS [root@centos7 ~] # nmcli con modify eth0 ipv4.dns 8.8.8.8

All the above editing operations need to be restarted to take effect:

[root@centos7 ~] # nmcli con down eth0;nmcli con up eth0 # restart takes effect

Usage: nmcli device {COMMAND | help}

COMMAND: = {status | show | connect | disconnect | delete | wifi}

Status: displays the status of all interfaces

Show []: displays the details of the specified interface

Connect: connect to the specified interface

Disconnect: disconnects the specified interface

Delete: deletes the specified interface

[root@centos7 ~] # nmcli dev show eth0GENERAL.DEVICE: eth0GENERAL.TYPE: ethernetGENERAL.HWADDR: 00:0C:29:01:DC:01GENERAL.MTU: 1500GENERAL.STATE: 100 (connected) GENERAL.CONNECTION: Eth0GENERAL.CON-PATH: / org/freedesktop/NetworkManager/ActiveConnection/4WIRED-PROPERTIES.CARRIER: onIP4.ADDRESS [1]: 192.168.52.7/24IP4.GATEWAY: 192.168.52.2IP6.ADDRESS [1]: fe80::20c:29ff:fe01:dc01/64IP6.GATEWAY:

(5) tui tool for network interface configuration: nmtui

[root@centos7 ~] # nmtui

(6) Host name configuration tool: hostnamectl {status | set-hostname}

[root@centos7 ~] # hostnamectl status Static hostname: localhost.localdomain Icon name: computer Chassis: n Machine ID:800b1ae9531f4c38964ddd3322f4624b Boot ID:ec6a5610e3444e668bed2c81bc981a5d Virtualization a Machine ID:800b1ae9531f4c38964ddd3322f4624b Boot ID:ec6a5610e3444e668bed2c81bc981a5d Virtualization: vmware Operating System: CentOS Linux 7 (Core) CPE OS Name: cpe:/o:centos:centos:7 Kernel: Linux 3.10.0-229.el7.x86_64 Architecture: x86 * 64 [root@centos7 ~] # hostnamectl set-hostname Centos7 # takes effect permanently

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