To check firewall status in an UBUNTU machine

ufw status
Status: active

To Action From
-- ------ ----
22/tcp ALLOW Anywhere
22/tcp (v6) ALLOW Anywhere (v6)

Check rules by number

ufw status numbered
 To                         Action      From
 --                         ------      ----
[ 1] 22/tcp ALLOW IN Anywhere
[ 2] 80/tcp ALLOW IN Anywhere
[ 3] 22/tcp (v6) ALLOW IN Anywhere (v6)
[ 4] 80/tcp (v6) ALLOW IN Anywhere (v6)

Delete rule by number

 ufw delete 3
Deleting:
 allow 80/tcp
Proceed with operation (y|n)? y
Rule deleted (v6)