How to check if ports are open on VPS?
If you are not sure if a certain port is open, you can always check it as explained below.
method 1: use command line
a) Right-click on the start menu -> Select Command Prompt (Admin).
b) Type this command to check then hit enter :
netsh firewall show state
netstat -a -n
As the output below shows your VPS is not blocked any port, you can open any port you want in firewall: How to open a port in Windows Server Firewall
As VPS we are using for you write this you can see I have 3 ports open :443, 3650,161
method 2 : By Using Apps
There are many websites that check port status. Here I am using website: https://portchecker.co/ for test
a) Go to the website.
b) Enter your IP address or click on use current IP.
c) Enter a Port number or select from the drop-down menu on the right side.
d) Click Check.
You will see which ports are open and which ones are closed.
2. On Linux
a) Launch Linux terminal application.
b) Type command:
netstat -tulpn | grep LISTEN
lsof -i -P -n | grep LISTEN
Any of these three commands can tell you which ports are open.
method 2: Use telnet
a)Open Terminal on your Linux
b) Install Telnet on linux
For Centos : yum install telnet
For Ubuntu/Debian: apt-get install telnet
c) Enter “telnet + your IP address + port number” (e.g: telnet 45.92.x.x 3650) to run the telnet command and test the port status.
d)If the port is open, a message will say Connected to 45.92.x.x
If the port is closed, a message will say Connection refused.
3. On Mac
a) Click the Spotlight icon in the upper-right hand corner or press Command + Space bar
b) Type “Terminal” in the search field and select Terminal.
c) Enter “nc -zv + your IP address + port number” (e.g: nc -zv 203.24.x.x 4000 ) to run the telnet command and test the port status.
d) If the port is open, a message will say Connection to 203.24.x.x port 4000 [udp/https] succeeded!
If the port is closed, a message will say nc: connectx to 203.24.x.x port 4000 (tcp) failed: Connection refused.
Usually, you don’t have to worry about ports, your Operating System, network hardware, and application manage them. However, it is always a good idea to keep tools handy in case anything goes wrong and you need to figure out what is causing the issue.
Opening or closing the ports or finding if a port is open or not is not a difficult task. You just have to know the right keys to push.