What Exactly Is "passive Mode" ? What seems to be its exact function and meaning?

I was wondering if someone could explain to me what exactly "Passive Mode" is, and, given the name, what exactly is "passive" about the connection you are establishing.

 

I am asking because there is (there probably would be, if one exists, it probably has its proper opposite), whenever I use an FTP client or a built-in FTP module (eg. in a HTML editor) usually the following choice:

 

Active Mode

Passive Mode

Default Mode

So, since there is a default mode present as well, this either tells me there is a mode that is neither passive nor active, or that certain servers are set passive or active by default.

 

So, the first reason why I am asking this question is because I am curious what is active or passive about what happens during the file transfers, but there is another reason too:

 

As long as I can remember, whenever I used an FTP client or a program with built-in FTP in the past, the program was always set to passive mode by default, and that always seemed to work fine.

 

However, lately I have began to run into problems using the following programs:

 

FileZilla

CoffeeCup HTML Editor

Simfatic Forms

I am sure everyone knows the first one, the second one is, as the name implies, a HTML Editor, which has, like all HTML Editors, a built-in upload manager, and the third one is a program for generating web forms, also with a built in file transfer manager.

 

As I said before, like I had always known, all my FTP programs were always set to passive mode by default, and that always worked great, however, with FileZilla, I have began to experience glitches in the transfers for a while, and changing from passive mode or automatic detection to active mode seems to have helped.

 

With CoffeeCup, I had been having trouble uploading for quite some time, either it took ages for the file transfer to start, or the transfer timed out altogether, the advice on their forum was to try and switch off passive mode and see if that made any difference.

I did that, and in the beginning, it wouldn't even let me connect to the server, but after trying again, it has made a slight improvement.

 

With Simfatic Forms, everything used to work perfectly, uploading went nice and smooth communication with the server and MySQL happened with no problem, until recently, it all happened after a reformat and hence a re-install of the program.

I had the greatest troublr uploading, often had to resort to manual uploading, uploads would time out or not be able to connect to the server at all, I tried everything, until, just a gamble, I must admit, I unticked the feature "Passive Mode", and, HOP, problem solved.

 

So, I am still wondering why everything always used to have Passive Mode by default, and that was also what was recommended, while now, recently, it seems like Passive Mode has become really "passive" (in that it does not seem to do much anymore).

 

Has anyone got some explanations for me, please?

 

Thank you in advance.

Active and passive mode dictate who is in control of the connection. In active mode, the client sends the server their IP address and a port that the client will listen on. This works well for most people, but can cause problems on networks and with firewalls. In passive mode, the server tells the client the server's IP address and a port the server will listen on. In passive mode, the client opens the connection to the server, and therefore it gets around most firewalls.

Right,that is very plainly and clearly explained.Thanks for that, first of all.So, if I understand correctly, having to switch modes on my applications for File Transfers might have had something to do with the fact that I changed from Windows Firewall to ZoneAlarm, am I right in thinking that?I think you do not have sufficient control over Windows Firewall anyway, the main things you can do with it are switch it on or off, and add or block a program in it, while control over ports and web sites are a real nightmare (well, that is my opinion anyway).I still think I did the right thing in changing Firewalls, in spite of the few problems I had to make FTP work properly, however, if there is any further advice available on better solutions, or better firewalls, I am always open to suggestions.Thanks for the explanation.And thanks in advance for any further advice I might receive.

Edited September 20, 2011 by mrdee (see edit history)