【Linux operation 38】解决Linux 端口被占用

1、前言

最近在linux服务器上部署应用，总是出现端口被占用的情况，有时关闭软件，kill进程也会出现端口占用。
有时候关闭软件后，后台进程死掉，也会导致端口被占用。

2、解决方法

2.1、查找被占用的端口

命令：netstat -nultp
#netstat -nultp #查看端口使用情况
#netstat -nultp | grep 22 #只查看端口22的使用情况

linux-3v74:~ # netstat -nultp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name   
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1656/sshd           
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      1782/master         
tcp        0      0 :::22                   :::*                    LISTEN      1656/sshd           
tcp        0      0 ::1:25                  :::*                    LISTEN      1782/master         
udp        0      0 0.0.0.0:68              0.0.0.0:*                           1001/wickedd-dhcp4  

linux-3v74:~ # netstat -nultp | grep 22
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1656/sshd           
tcp        0      0 :::22                   :::*                    LISTEN      1656/sshd 

命令： netstat -anp
#netstat -anp #查看端口使用情况
#netstat -anp | grep 22 #只查看端口22的使用情况

linux-3v74:~ # netstat -anp
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name   
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1656/sshd           
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      1782/master         
tcp        0      0 10.169.42.82:22         10.169.42.154:54363     ESTABLISHED 1861/sshd: root     
tcp        0      0 10.169.42.82:22         10.169.42.154:54364     ESTABLISHED 1876/sshd: root@not 
tcp        0    148 10.169.42.82:22         10.169.42.86:58230      ESTABLISHED 1964/1              
tcp        0      0 :::22                   :::*                    LISTEN      1656/sshd           
tcp        0      0 ::1:25                  :::*                    LISTEN      1782/master         
udp        0      0 0.0.0.0:68              0.0.0.0:*                           1001/wickedd-dhcp4  
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags       Type       State         I-Node PID/Program name    Path
unix  2      [ ]         DGRAM                    15124  1/systemd           /run/systemd/journal/syslog
unix  2      [ ACC ]     STREAM     LISTENING     27625  1826/gnome-session- @/tmp/.ICE-unix/1826
unix  2      [ ACC ]     SEQPACKET  LISTENING     15128  1/systemd           /run/udev/control
unix  2      [ ACC ]     STREAM     LISTENING     15132  1/systemd           /run/lvm/lvmetad.socket
......

linux-3v74:~ # netstat -anp | grep 22
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1656/sshd           
tcp        0      0 10.169.42.82:22         10.169.42.154:54363     ESTABLISHED 1861/sshd: root     
tcp        0      0 10.169.42.82:22         10.169.42.154:54364     ESTABLISHED 1876/sshd: root@not 
tcp        0     52 10.169.42.82:22         10.169.42.86:58230      ESTABLISHED 1964/1              
tcp        0      0 :::22                   :::*                    LISTEN      1656/sshd           
unix  2      [ ACC ]     STREAM     LISTENING     22820  984/nscd            /var/run/nscd/socket
unix  2      [ ACC ]     STREAM     LISTENING     22337  1/systemd           /var/run/pcscd/pcscd.comm
unix  2      [ ACC ]     STREAM     LISTENING     22340  1/systemd           /run/dbus/system_bus_socket
unix  2      [ ]         DGRAM                    27467  1822/systemd        /run/user/484/systemd/notify
unix  2      [ ACC ]     STREAM     LISTENING     27469  1822/systemd        /run/user/484/systemd/private
unix  2      [ ACC ]     STREAM     LISTENING     27322  1742/gdm-simple-sla @/tmp/dbus-6GUvF5JW
unix  2      [ ACC ]     STREAM     LISTENING     22343  1/systemd           @ISCSIADM_ABSTRACT_NAMESPACE
unix  22     [ ]         DGRAM                    10944  1/systemd           /run/systemd/journal/dev-log
unix  3      [ ]         STREAM     CONNECTED     22784  1/systemd           /run/systemd/journal/stdout
unix  3      [ ]         STREAM     CONNECTED     22782  981/dbus-daemon     
unix  3      [ ]         STREAM     CONNECTED     27522  1836/at-spi-bus-lau 
unix  3      [ ]         STREAM     CONNECTED     22862  981/dbus-daemon     
unix  3      [ ]         STREAM     CONNECTED     22864  981/dbus-daemon     /run/dbus/system_bus_socket
unix  3      [ ]         STREAM     CONNECTED     27440  1822/systemd        
unix  2      [ ]         DGRAM                    22799  984/nscd            
unix  3      [ ]         STREAM     CONNECTED     22449  974/VGAuthService   
unix  3      [ ]         STREAM     CONNECTED     22356  1/systemd           
unix  3      [ ]         STREAM     CONNECTED     22450  1/systemd           /run/systemd/journal/stdout
unix  3      [ ]         STREAM     CONNECTED     22863  981/dbus-daemon     
unix  3      [ ]         STREAM     CONNECTED     23622  1057/wickedd-nanny  
unix  2      [ ]         DGRAM                    27455  1822/systemd        
unix  3      [ ]         STREAM     CONNECTED     26622  1782/master         
linux-3v74:~ # 

2.2、查看端口属于哪个程序？端口被哪个进程占用

命令：lsof -i :22
#如果用lsof -i命令查不到端口， 安装一下就ok了 yum install lsof -y
Tip : lsof -i 需要 root 用户的权限来执行

linux-3v74:~ # lsof -i :22
COMMAND  PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
sshd    1656 root    3u  IPv4  25129      0t0  TCP *:ssh (LISTEN)
sshd    1656 root    4u  IPv6  25135      0t0  TCP *:ssh (LISTEN)
sshd    1861 root    4u  IPv4  27727      0t0  TCP 10.169.42.82:ssh->CN-W-GRSTV63.INT.vertivco.com:54363 (ESTABLISHED)
sshd    1876 root    4u  IPv4  27827      0t0  TCP 10.169.42.82:ssh->CN-W-GRSTV63.INT.vertivco.com:54364 (ESTABLISHED)
sshd    1964 root    4u  IPv4  30076      0t0  TCP 10.169.42.82:ssh->DESKTOP-47MK0MU.INT.vertivco.com:58230 (ESTABLISHED)

2.3、杀掉占用端口的进程

在查到端口占用的进程后，如果你要杀掉对应的进程可以使用 kill 命令：

kill -9 PID