Network Configuration

Setting up FTP is not easy. Since thousands of different firewalls and router models exist, it is impossible to give detailed step-by-step instructions suitable for every user. So in order to configure FileZilla as well as the routers/firewalls involved, it is important for the user to understand the basics of the FTP protocol. This documentation describes the history of the FTP protocol and how some aspects of the protocol work. Please read it carefully, it will save you a lot of trouble setting up FTP.

Background

This section will give a short overview about the historical and technical background of the FTP protocol. For detailed in-depth information, please have a look at the specifications.

Historical Background

In the fast living world of the Internet the FTP protocol is not just old, it's ancient. Early drafts of the FTP protocol range back as far as 1971, with the current specifications being from 1985. During the past two decades, the FTP protocol hasn't changed at all in its core. The protocol might even be older than You!

Back then, the Internet was mainly used by universities and research centers. The comminity were small, most users knew each other and all were collaborating together. The internet was a friendly place. Security was not a big issue. People either did not know about that topic or were ignorant to it.

Since then, a lot has changed. Technology advanced way faster than anyone imagined and a new generation of users was born and grew up. The Internet is now ubiquitous, with millions of users communicating with each other in many different ways. One more thing has changed: The internet is now a hostile place. The availability and openess of the internet also attracted malicious users who are actively exploiting design flaws, bugs and the inexperience of other users. A well known software company located in Redmond certainly played a part in this.

Some of the by-products of this development are the following:

• NAT routers. Most of the internet uses the IPv4 protocol which has a very limited address range. Thanks to NAT routers, multiple systems can easily share the same external IP address.
• Personal firewalls which are designed to protect the user from flaws in the operating system and the applications running on top of it.

These products tend to conflict with the FTP protocol more often than not. To make things worse, some of them even have flaws themselves, causing additional problems regarding FTP.

With proper configuration however, FTP still works as a mature, reliable way to transfer files.