Use !scan-port-ip4 to scan UDP, TCP, and SCTP ports on hosts in the IPv4 Internet.
You can also use !scan-port in place of !scan-port-ip4
Pass to !scan-port-ip4 an IP socket and a protocol type. TCP is used if the protocol type is omitted.
Use !scan-port to debug connectivity, firewall, and NAT issues on Internet Services.There are many IPduh !scan commands but most of them may return cached-stale results which are no suitable for real-time debugging and experiments. !scan-port and !scan-port-ip4 will always show you fresh scan results.
Like most IPduh commands, !scan-port-ip4 is an independent implementation, hence it may help you see something that other tools may miss.
Note: When debugging Internet Services your scan results need to be fresh. If your local caching subsystem or some immediate cache has a mind of its own and thinks that knows better than the content provider (IPduh) or You what You actually want, try an equivalent variation of your !scan-port-ip4 command before switching web-browser or web-view or start looking into how to evade your network's policies. As you can see in the examples above, there are at least two ways of saying the same thing producing at least two URL signatures for an HTTP-cache.
To verify that an IPduh scan is fresh look at the epoch-timestamp and the little numbers at the bottom of the page. It is highly unlikable for these numbers to not change in between requested scans. If these numbers remain the same in between scans you are watching a cached page.