ubuntu open ports code example

Example 1: ubuntu listening ports

# To see ports in use
sudo lsof -i -P -n | grep LISTEN 
sudo netstat -tulpn | grep LISTEN

Example 2: ubuntu open port

sudo ufw allow 1191/tcp

Example 3: open firewall port in linux

Debian: sudo ufw allow PORT. CentOS: sudo firewall-cmd --zone=public --permanent --add-port=PORT/tcp sudo firewall-cmd --reload

Example 4: ubuntu open all port

sudo ufw allow 1:9999/tcp