Using telnet command :
Syntax : telnet <Host_name> <port_no>
telnet test.openspecimen.org 80 |
Use the above command from outside the server machine. If port 80 is open. "Connected to test.openspecimen.org." message will be displayed on the terminal.
Listing down iptables rules. Below is the command to list iptables rules :
sudo iptables -L |
Check if there is any rule set for port 80, in the same row if under 'Target' column DROP option is present then port 80 is blocked.
The below commands will display open ports of the server.
Operating system | command |
---|---|
Ubuntu | sudo ufw status |
CentOS / RHEL | sudo firewall-cmd --list-all |