Linux iptables turn on and off the service port number

Requirements: The simulation database hangs, the service is normal but access to the database error, after recovering the database port, the service can access the database normally

Step: First, disconnect the port number 5432, test the operation of the service, and secondly, turn on the port number 5432, test the service running condition;

Specific operation:

1, break down port number

A, log on to the server

b, view port number connection:telnet localhost 5432

C, break start slogan: sudo iptables-a input-p tcp--dport 5432-j ACCEPT

sudo iptables-a output-p tcp--dport 5432-j ACCEPT

D, view port number connection:telnet localhost 5432

2, turn on the port number

A, view the list of rules: sudo iptables-l-n

B, delete the drop rule: sudo iptables-d INPUT 1

sudo iptables-d OUTPUT 1

c, see if the rule is deleted: sudo iptables-l-n

D, look at the port number connection condition: telnet localhost 5432

Linux iptables turn on and off the service port number