Gavin Pearce

It’s very easy to check which ports are listening on your server before IPTABLES and your Firewall takes affect.

SSH command:

netstat -lptu

However, getting a list of open ports after IPTABLES and your Firewall have done their job requires a Port Scan. To get the fairest results this needs to be done from a different machine (depending on your IPTABLES/Firewall config, and what it is you’re trying to test).

SSH command:

nmap 192.0.32.10

You might also find this useful.

SSH command:

nmap -sS -p0-65535 -P0 -T4 --osscan_limit --osscan_guess --host_timeout 15m --max-retries 0 --min_parallelism 100 --max_parallelism 500 -O -oX -V 192.168.1.1