How to open a port on Kali Linux?

Question

firewall

Can't open port 23 on Kali Linux ARM64 (Raspberry pi 4)
Tried via ufw allow 23and via iptables. did not help.
Checked through nmap and telnet.

Answer 1

Hmm? Is anyone listening on port 23? Check via nestat -natp|grep :23. If the screen is not empty - then listen to whether packets arrive or not via tcpdump -nni any port 23.
What command did you use to add the iptables rule?