Open the port: If you want to open the port, just select "Automatic" in the startup type, click "OK" button, then open the service, click "Start" button to enable the port in the service status, and finally click "OK" button. Close the port: For example, to close port 25 of SMTP service in Windows2000/XP, you can do this: first open the control panel, double-click the administrative tools, and then double-click the service. Then find and double-click the Simple Transfer Protocol (SMTP) service in the opened service window, click the Stop button to stop the service, then select Disable in the Startup Type, and finally click the OK button. In this way, closing the SMTP service is equivalent to closing the corresponding port.
How does linux check whether useless ports are closed?
You can use the command netstat to see if useless ports are closed.
How to check which program of linux occupies the port?
Check the port usage and use the netstat command.
View connected service ports (ESTABLISHEDnetstat-a) View all service ports (LISTEN, ESTABLISHED)netstat-ap View port 8080, and then you can combine the grep command: netstat-ap|grep8080 If you view port 8888, enter: lsof-i:8888 How can I find out the list of all open ports in Linux?
Use the command netstat-antu to check the openness of all tcp and udp ports, where -a means to check all ports, and by default, only viewing the connected n means to display the numerical port number without displaying the name, for example, displaying 80 instead of httpt means that tcp port u means udp port.
Does linux check whether the port of ntp server is open?
NTP is a service for synchronizing computer time. It is managed by ntpd service in linux. Under the condition that the ntpd service is started normally, the NTP service will synchronize the time through UDP 123 port. You can use the following command to check the port occupancy:
Ss-unlp|grepntp, if there is an echo, the port displays 123, indicating that the ntp service port has been opened.