how to close linux port

How to close the linux port?

How to open and close ports in Linux

1. Check which ports are open netstat -anp

2. Close the port number :

iptables -A OUTPUT -p tcp --dport 端口号-j DROP

3. Open the port number:

iptables -A INPUT -ptcp --dport  端口号-j ACCEPT

4. Save the settings

service iptables save

5. The following is how to use the Linux open port command.

　　nc -lp 23 &(打开23端口，即telnet)
　　netstat -an | grep 23 (查看是否打开23端口)

6. Linux open port command Each open port needs a corresponding listening program

Recommended Linux video tutorial, learning address: https://www .php.cn/course/list/33.html

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