I have read other topics with this question, but there is no answer to my question anywhere. Sorry.
The problem is that the flag that is in ibm-db2 is not suitable. In addition to everything, it does not work to get this flag through kali, but through the htb machine it turns out that there is no “filtered” and reason “no-response”
Have you tried to scan the network with -sA? This is effective with a machine having firewalls because it is just makeing a ACK and not making a real like connection to it.
Follow steps from SYN-Scan of a Filtered Port to Connect To The Filtered Port and don’t forget to use your elevated privileges. 