Creating iptables Rulesets It's a great starting-point for ruleset development to see what ports are currently in-use, and consider that these may need to be opened through our firewall. To see what ports are in-use, and by what programs/services: hostname ~ # netstat -alnp Annotated link http://www.diigo.com/bookmark/http%3A%2F%2Fjviz.research.iat.sfu.ca%2Fwiki%2Findex.php%3Ftitle%3DHOWTO_Setup_iptables