Listet auf, welche Ports man für welche Services (DNS, HTTP, SMTP, POP, IMAP, FTP, etc.) wie (intern, extern und Range) offen haben muss, damit der Service funktioniert.
The following is an example iptables firewall that allows incoming ssh connections from an individual IP address (192.168.1.100), allows all outbound traffic, and uses stateful inspection.
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