Just to extend the answer of @xenoterracide You can read more about iptables in the manpage iptables(8) (type man 8 iptables) but there you will not find --dport or --sport.These options are listed in iptables-extensions(8) in the section multiport, tcp, udp and elsewhere. This might be interesting to you.
Mar 23, 2020 Docker: Port Forwarding for Docker Container through First we should check port 80 on Docker Host machine. #nc -w 5 -v 192.168.43.47 80 nc: connect to 192.168.43.47 port 80 (tcp) failed: No route to host Let’s deploy IPTables for Docker Container IP Address: 172.17.0.3 [리눅스 iptables] port 열기 / 방화벽 켜고 끄기. : 네이버 블로그
Feb 15, 2019
IptablesHowTo - Community Help Wiki
Easy IPTables Configuration and Examples on Ubuntu 16.04
Mar 04, 2015 How to Check Open Ports in Linux - LinOxide Sep 25, 2019 Easy IPTables Configuration and Examples on Ubuntu 16.04 Jan 29, 2018 CentOS / RHEL : How to configure iptable rules to allow On the FTP Server, by default iptables rules are not set to allow port 20/21 for FTP connection. Use the procedure described below to open the FTP ports 20 and 21 in iptables. CentOS / RHEL : How to configure iptable rules to allow FTP ports 20/21 – The Geek Diary