Linux - 常用网络操作

时间：2022-07-31 16:39:58

01 - Linux虚拟机出现多个默认路由，导致部分网络连接异常

# route -n

Kernel IP routing table

Destination     Gateway         Genmask         Flags Metric Ref    Use Iface

0.0.0.0         192.168.16.1    0.0.0.0         UG    100    0        0 enp0s3

0.0.0.0         10.0.3.2        0.0.0.0         UG    101    0        0 enp0s8

......

处理方法：更改网关192.168.16.1的路由设置。

  • CentOS7：应用程序---》系统工具---》设置---》网络---》以太网（enp0s3），点击右下角的设置按钮---》IPv4---》选择“仅对此网络上的资源使用此连接”---》应用。
  • Ubuntu1604：系统设置---》网络---》有线，选择对应网卡---》选项---》IPv4设置---》路由---》选择“仅将此连接用于相对应的网络上的资源”---》确定。
# route -n

......

192.168.16.0    0.0.0.0         255.255.255.0   U     100    0        0 enp0s3

......

02 - Linux查看端口状态

检测本机8080端口状态：netstat –apn | grep 8080

检测192.168.0.1主机的8080端口状态：telnet 192.168.0.1 8080 或nmap -sS -P0 -n -p 22 192.168.0.1

检测192.168.0.1主机的1到1024端口状态：nc -z 192.168.0.1 1-1024

# nmap -sS -P0 -n -p 22 10.140.0.135

Starting Nmap 6.40 ( http://nmap.org ) at 2016-11-09 10:42 CST

Nmap scan report for 10.140.0.135

Host is up (0.00040s latency).

PORT STATE SERVICE

22/tcp open ssh

MAC Address: 08:00:27:3F:19:79 (Cadmus Computer Systems)

Nmap done: 1 IP address (1 host up) scanned in 0.07 seconds

# nmap -sS -P0 -n -p 80 10.140.0.135

Starting Nmap 6.40 ( http://nmap.org ) at 2016-11-09 10:50 CST

Nmap scan report for 10.140.0.135

Host is up (0.00046s latency).

PORT STATE SERVICE

80/tcp closed http

MAC Address: 08:00:27:3F:19:79 (Cadmus Computer Systems)

Nmap done: 1 IP address (1 host up) scanned in 0.06 seconds

03 - Linux命令行设置CentOS计算机名称、hosts及网卡地址

$ echo "anliven" > /etc/hostname

$ echo -e "192.168.16.166 master\n192.168.16.167 slave01\n192.168.16.168 slave02" >> /etc/hosts

$ sed -i '/IPADDR/s/192.168.16.200/192.168.16.166/' /etc/sysconfig/network-scripts/ifcfg-enp0s8

$ reboot

04 - Linux CentOS7关闭SELinux

  • 永久方法：修改/etc/selinux/config文件中设置SELINUX=disabled ，然后重启。
# getenforce

Enforcing

# sed -i '/SELINUX/s/enforcing/disabled/' /etc/selinux/config

# reboot
  • 临时方法：执行setenforce 0命令设置SELinux成为permissive模式
sudo systemctl status firewalld.service

sudo systemctl stop firewalld.service

sudo systemctl disable firewalld.service

05 - Ubuntu安装ssh并允许root登录

  1. Install openssh-server
apt-get update

apt-get install openssh-server
  1. Change ssh configuration
root@anliven:~# vim /etc/ssh/sshd_config

root@anliven:~#

root@anliven:~# cat /etc/ssh/sshd_config |grep RootLogin

#PermitRootLogin without-password

PermitRootLogin yes

# the setting of "PermitRootLogin without-password".

root@anliven:~#

root@anliven:~# /etc/init.d/ssh restart

ssh stop/waiting

ssh start/running, process 3782

root@anliven:~#
  1. Check ssh status
root@anliven:~# lsof -i:22

COMMAND  PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME

sshd    3630 root    3u  IPv4  19611      0t0  TCP *:ssh (LISTEN)

sshd    3630 root    4u  IPv6  19613      0t0  TCP *:ssh (LISTEN)

root@anliven:~#

root@anliven:~# ps -ef |grep ssh

root      3630     1  0 13:43 ?        00:00:00 /usr/sbin/sshd -D

root      3750  3732  0 13:46 pts/1    00:00:00 grep --color=auto ssh

root@anliven:~#

06 - Linux常用网络软件包

  • inetuils-ping --- ping
  • net-tools --- ifconfig/route/netstat/......
  • iproute --- ip
  • traceroute
  • bind-utils --- nslookup/dig/host/......
  • bridge-utils --- brctl
  • nmap
  • tcpdump
  • wireshark
  • curl
  • wget

    ......

07 - Linux设置ssh免密码认证

示例：slave01和slave02两个主机ssh免密码相互登录

### 设置slave01 node

[hadoop@slave01 ~]$ ssh-keygen

[hadoop@slave01 ~]$

[hadoop@slave01 ~]$ cd .ssh

[hadoop@slave01 .ssh]$ ssh-copy-id -i hadoop@slave01

[hadoop@slave01 .ssh]$ ssh-copy-id -i hadoop@slave02

[hadoop@slave01 .ssh]$

[hadoop@slave01 .ssh]$ ll -a

total 20

drwx------  2 hadoop hadoop   76 Mar  7 23:34 .

drwx------. 6 hadoop hadoop 4096 Mar  7 23:30 ..

-rw-------  1 hadoop hadoop 1187 Mar  7 23:34 authorized_keys

-rw-------  1 hadoop hadoop 1675 Mar  7 23:33 id_rsa

-rw-r--r--  1 hadoop hadoop  396 Mar  7 23:33 id_rsa.pub

-rw-r--r--  1 hadoop hadoop  551 Mar  7 23:34 known_hosts

[hadoop@slave01 .ssh]$ 

### 设置slave02 node

[hadoop@slave02 ~]$ ssh-keygen

[hadoop@slave02 ~]$

[hadoop@slave02 ~]$ cd .ssh

[hadoop@slave02 .ssh]$ ssh-copy-id -i hadoop@slave01

[hadoop@slave02 .ssh]$ ssh-copy-id -i hadoop@slave02

[hadoop@slave02 .ssh]$

[hadoop@slave02 .ssh]$ ll -a

total 20

drwx------  2 hadoop hadoop   76 Mar  7 23:35 .

drwx------. 6 hadoop hadoop 4096 Mar  7 23:30 ..

-rw-------  1 hadoop hadoop 1187 Mar  7 23:35 authorized_keys

-rw-------  1 hadoop hadoop 1675 Mar  7 23:33 id_rsa

-rw-r--r--  1 hadoop hadoop  396 Mar  7 23:33 id_rsa.pub

-rw-r--r--  1 hadoop hadoop  551 Mar  7 23:35 known_hosts

[hadoop@slave01 .ssh]$

08 - Linux设置路由并指定metric值

  • 默认路由：route add default gw 10.0.2.2 metric 1
  • 指定路由：route add 192.168.0.0 mask 255.255.0.0 192.168.16.1 metric 10

09 -xxx

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