How to check ports in Linux

How to check the port in Linux

1,lsof -i: The port number is used Check the usage of a certain port, for example, check the usage of port 8000, lsof -i:8000

# lsof -i:8000 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME lwfs 22065 root 6u IPv4 4395053 0t0 TCP *:irdmi (LISTEN)

You can see that port 8000 has been occupied by the lightweight file system forwarding service lwfs

2,netstat -tunlp |grepPort number, used to check the process status of the specified port number, such as checking the status of port 8000, netstat -tunlp |grep 8000

# netstat -tunlp Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 4814/rpcbind tcp 0 0 0.0.0.0:5908 0.0.0.0:* LISTEN 25492/qemu-kvm tcp 0 0 0.0.0.0:6996 0.0.0.0:* LISTEN 22065/lwfs tcp 0 0 192.168.122.1:53 0.0.0.0:* LISTEN 38296/dnsmasq tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 5278/sshd tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 5013/cupsd tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 5962/master tcp 0 0 0.0.0.0:8666 0.0.0.0:* LISTEN 44868/lwfs tcp 0 0 0.0.0.0:8000 0.0.0.0:* LISTEN 22065/lwfs

# netstat -tunlp | grep 8000 tcp 0 0 0.0.0.0:8000 0.0.0.0:* LISTEN 22065/lwfs

Explain the meaning of several parameters:

-t (tcp) 仅显示tcp相关选项 -u (udp)仅显示udp相关选项 -n 拒绝显示别名，能显示数字的全部转化为数字 -l 仅列出在Listen(监听)的服务状态 -p 显示建立相关链接的程序名

Attach a python port occupancy monitoring program, which can monitor whether the port of the specified IP is occupied.

#!/usr/bin/env python # -*- coding:utf-8 -*- import socket, time, thread socket.setdefaulttimeout(3) #设置默认超时时间 def socket_port(ip, port): """ 输入IP和端口号，扫描判断端口是否占用 """ try: if port >=65535: print u'端口扫描结束' s=socket.socket(socket.AF_INET, socket.SOCK_STREAM) result=s.connect_ex((ip, port)) if result==0: lock.acquire() print ip,u':',port,u'端口已占用' lock.release() except: print u'端口扫描异常' def ip_scan(ip): """ 输入IP，扫描IP的0-65534端口情况 """ try: print u'开始扫描 %s' % ip start_time=time.time() for i in range(0,65534): thread.start_new_thread(socket_port,(ip, int(i))) print u'扫描端口完成，总共用时：%.2f' %(time.time()-start_time) # raw_input("Press Enter to Exit") except: print u'扫描ip出错' if __name__=='__main__': url=raw_input('Input the ip you want to scan: ') lock=thread.allocate_lock() ip_scan(url)

The execution results of this program are as follows:

# python scan_port.py Input the ip you want to scan: 20.0.208.112 开始扫描 20.0.208.112 20.0.208.112 : 111 端口已占用 20.0.208.112 : 22 端口已占用 20.0.208.112 : 8000 端口已占用 20.0.208.112 : 15996 端口已占用 20.0.208.112 : 41734 端口已占用 扫描端口完成，总共用时：9.38

Recommended related Linux video tutorials: "Linux Tutorial"

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