Firewall softwares such as norton internet security, Windows Firewall(ICF), TrendMicro PC-Cillin and are usually installed on many people's operating system, they can protect Your PC from internet hackers, but can also interfere with Server softwares.

To run a FTP server (RaidenFTPD ftp server) properly after a Firewall software, You have to configure the firewall properly, first of all we'll tell You the basic principles:

A. Open the following ports on Your firewall for bi-directions (in and out) TCP connections.
1. server port
2. implicit ssl port
3. explicit ssl port
4. data ports (a range of ports)

What will these ports be? You can refer to Your RaidenFTPD server options window like the following:

B. For more restrictive firewalls (ex: hardware firewall and checkpoint firewall), do the following changes:
1. Change the TCP source port for active connections (PORT command) to 20 by editing the preference. This is because some of those firewall verifies the TCP source port or they deny the connections. The reason of why we didn't set it as default is because that more and more system administrators do this in purpose, they block FTP, so if You set it as 20 You can't even run a FTP server.

2. Remove the long welcome message: some poorly designed firewalls hang when a long FTP welcome message is displayed.