Information for firewall and router owners

Frequently Asked Questions about Quick 'n Easy FTP Server
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Information for firewall and router owners

Post by admin » Sun May 22, 2005 3:46 pm

This section gives some information about how to configure routers and firewalls.

These days almost every computer is connected to the Internet using either a router and/or firewall. To be able to run a FTP Server you will need to configure this firewall/router to allow certain ports through to the FTP server. This usually involves either accessing the software (if it's a software router or firewall) or accessing a HTML interface (if it's a hardware router or firewall). There is (almost) always an option where you can choose a port to accept connections on and a destination computer and port which the connection will be routed to.

Step 1: For the FTP server to function correctly, port 21 needs to be forwarded.

Once someone is connected to your FTP Server, he probably wants to list or access (download/upload) the files on your server.
The FTP protocol uses a second connection to transfer this data (called the data connection).
The port(s) used to make this connection also need to be configured correctly.

The FTP protocol has 2 modes, PORT (also called "regular" or "normal" mode) and PASV ("passive" mode).

Step 2: If users connect to your server PORT mode, you have to tell your firewall that the server is allowed to access ALL outgoing ports.

If users use PASV mode, you need to configure the FTP server's PASV mode settings:
Step 3: First enter the IP address of your router of specify 'Get IP from remote server'.
Step 4: Enter a port range for the FTP server in PASV mode.

Examples:
port range 1024 - 65535 (default: ports 1024 till 65535 will be used)
port range 20 - 20 (only port 20 will be used)
port range 0 - 0 (a random port will be used (no limits))

Although it's probably safer to configure fewer ports, it's also slower because when a particular port is in use, other clients have to wait until the port becomes available again.
Note: When you have configured 5 simultaneous connections (Max. Connections), you'll only have to specify a range of 5 ports.

Step 5: Forward all ports in the range to the FTP server (on the router) and open them on your firewall for incoming connections.

For more information how to configure you type of router please check out this website: http://www.portforward.com/routers.htm
This site is dedicated to port fowarding and has detailed descriptions for almost every router on the planet.