ufw allow custom port ex 3000

 For allow custom port like 3000 with ufw firewall on ubuntu server just type:

ufw allow PORT --> ufw allow 3000

reload ufw

ufw reload

show status for ufw

ufw status 

or  

sudo ufw status verbose

for stop/disable 

ufw disable

for start ufw

ufw enable

for remove spesific rules

ufw delete [number]

back to default setting

ufw reset