I'm attempting to get an FTP client written in perl to transfer files from an IIS 7.5 FTP server using passive mode.

I've configured the FTP server as per instructions and have also configured Windows Firewall to allow this type of traffic. I have validated that the firewall is behaviong correctly by checking to ensure there are no blocked packets in the logs. I have verified the that FTP control channel is being opened on Port 21.

I believe the client is being told by IIS which port to connect on for passive mode and IIS is refusing to allow this connection.

The perl log looks like:

C:\cygwin\Perl\lib\FMT>perl FTPTest.pl
Net::FTP>>> Net::FTP(2.77)
Net::FTP>>>   Exporter(5.64_01)
Net::FTP>>>   Net::Cmd(2.29)
Net::FTP>>>   IO::Socket::INET(1.31)
Net::FTP>>>     IO::Socket(1.31)
Net::FTP>>>       IO::Handle(1.28)
Net::FTP=GLOB(0x20abac0)<<< 220 Microsoft FTP Service
Net::FTP=GLOB(0x20abac0)>>> USER ftpuser
Net::FTP=GLOB(0x20abac0)<<< 331 Password required for ftpuser.
Net::FTP=GLOB(0x20abac0)>>> PASS ....
Net::FTP=GLOB(0x20abac0)<<< 230 User logged in.
Net::FTP=GLOB(0x20abac0)>>> CWD /Logs
Net::FTP=GLOB(0x20abac0)<<< 250 CWD command successful.
Net::FTP=GLOB(0x20abac0)>>> PASV
Net::FTP=GLOB(0x20abac0)<<< 227 Entering Passive Mode (xx,xxx,xxx,xxx,160,41).
Net::FTP=GLOB(0x20abac0)>>> RETR filename.txt
Can't use an undefined value as a symbol reference at C:/Utilities/strawberryper
l/perl/lib/Net/FTP/dataconn.pm line 54.

IIS logs look as follows:

2010-10-02 17:40:06 xx.xxx.xx.xx - yy.y.yy.yy ControlChannelOpened - - 0 0 27a48c9b-9dce-4770-8bcf-fc89f2569b1a - -
2010-10-02 17:40:06 xx.xxx.xx.xx - yy.y.yy.yy USER ftpuser 331 0 0 27a48c9b-9dce-4770-8bcf-fc89f2569b1a - -
2010-10-02 17:40:06 xx.xxx.xx.xx MACHINENAME\ftpuser yy.y.yy.yy PASS *** 230 0 0 27a48c9b-9dce-4770-8bcf-fc89f2569b1a / -
2010-10-02 17:40:06 xx.xxx.xx.xx MACHINENAME\ftpuser yy.y.yy.yy CWD /Logs 250 0 0 27a48c9b-9dce-4770-8bcf-fc89f2569b1a /Logs -
2010-10-02 17:40:06 xx.xxx.xx.xx MACHINENAME\ftpuser yy.y.yy.yy PASV - 227 0 0 27a48c9b-9dce-4770-8bcf-fc89f2569b1a - -
2010-10-02 17:40:27 - MACHINENAME\ftpuser zz.z.zz.zzz 41001 DataChannelClosed - - 64 0 27a48c9b-9dce-4770-8bcf-fc89f2569b1a - -
2010-10-02 17:40:27 xx.xxx.xx.xx MACHINENAME\ftpuser yy.y.yy.yy ControlChannelClosed - - 64 0 27a48c9b-9dce-4770-8bcf-fc89f2569b1a - -
2010-10-02 17:40:27 xx.xxx.xx.xx MACHINENAME\ftpuser yy.y.yy.yy RETR filename.txt 550 1236 0 27a48c9b-9dce-4770-8bcf-fc89f2569b1a filename.txt -

We've managed to see this issue with other FTP clients also, I don't think its something funny in Perl. I've been informed that this works fine in the IIS 6 FTP server. I'm wondering if there is something we're missing here.