Active vs Passive mode FTP
Active FTP vs. Passive FTP, a Definitive Explanation Contents: Introduction The Basics Active FTP Active FTP Example Passive FTP Passive FTP Example Other Notes Summary References Appendix 1: Configuration of Common FTP Servers Introduction One of the most commonly seen questions when dealing with firewalls and other Internet connectivity issues is the difference between active and passive FTP and how best to support either or both of them. Hopefully the following text will help to clear up some of the confusion over how to support FTP in a firewalled environment. This may not be the definitive explanation, as the title claims, however, I've heard enough good feedback and seen this document linked in enough places to know that quite a few people have found it to be useful. I am always looking for ways to improve things though, and if you find something that is not quite clear or needs more explanation, please let me know! Recent additions to this document include the examples of b...