Cannot FTP from Internet

Hello and thank you for your time,

Here is my setup:

Linux server/router running Shorewall
Another Linux server running ProFTPd using port 2121 for FTP
A windows server running IIS using port 21 for FTP

I do have Shorewall DNAT port 2121 to ProFTPd

I can FTP into the Windows server from both the LAN and the Internet.
I can FTP into ProFTPd from within the LAN, but not the Internet.  When I try, I get the following from Filezilla:

Command:      PASV
Response:      227 Entering Passive Mode (192,168,217,20,223,142).
Status:      Server sent passive reply with unroutable address. Using server address instead.
Command:      MLSD
Error:      Connection timed out
Error:      Failed to retrieve directory listing

The log is:

2013-11-03 21:30:11 7504 3 Status: Resolving address of domain.net
2013-11-03 21:30:12 7504 3 Status: Connecting to xxx.xxx.xxx.xxx:2121...
2013-11-03 21:30:12 7504 3 Status: Connection established, waiting for welcome message...
2013-11-03 21:30:12 7504 3 Response: 220 ProFTPD 1.3.4a Server (Debian) [::ffff:192.168.217.20]
2013-11-03 21:30:12 7504 3 Command: USER userlogin
2013-11-03 21:30:12 7504 3 Response: 331 Password required for userlogin
2013-11-03 21:30:12 7504 3 Command: PASS *********
2013-11-03 21:30:12 7504 3 Response: 230 User userlogin logged in
2013-11-03 21:30:12 7504 3 Command: SYST
2013-11-03 21:30:12 7504 3 Response: 215 UNIX Type: L8
2013-11-03 21:30:12 7504 3 Command: FEAT
2013-11-03 21:30:12 7504 3 Response: 211-Features:
2013-11-03 21:30:12 7504 3 Response:  LANG en-US.UTF-8*;en-US
2013-11-03 21:30:12 7504 3 Response:  MDTM
2013-11-03 21:30:12 7504 3 Response:  MFMT
2013-11-03 21:30:12 7504 3 Response:  TVFS
2013-11-03 21:30:12 7504 3 Response:  UTF8
2013-11-03 21:30:12 7504 3 Response:  MFF modify;UNIX.group;UNIX.mode;
2013-11-03 21:30:12 7504 3 Response:  MLST modify*;perm*;size*;type*;unique*;UNIX.group*;UNIX.mode*;UNIX.owner*;
2013-11-03 21:30:12 7504 3 Response:  SITE MKDIR
2013-11-03 21:30:12 7504 3 Response:  SITE RMDIR
2013-11-03 21:30:12 7504 3 Response:  SITE UTIME
2013-11-03 21:30:12 7504 3 Response:  SITE SYMLINK
2013-11-03 21:30:12 7504 3 Response:  REST STREAM
2013-11-03 21:30:12 7504 3 Response:  SITE COPY
2013-11-03 21:30:12 7504 3 Response:  SIZE
2013-11-03 21:30:12 7504 3 Response: 211 End
2013-11-03 21:30:12 7504 3 Command: OPTS UTF8 ON
2013-11-03 21:30:12 7504 3 Response: 200 UTF8 set to on
2013-11-03 21:30:12 7504 3 Status: Connected
2013-11-03 21:30:12 7504 3 Status: Retrieving directory listing...
2013-11-03 21:30:12 7504 3 Command: PWD
2013-11-03 21:30:12 7504 3 Response: 257 "/var/www" is the current directory
2013-11-03 21:30:12 7504 3 Command: TYPE I
2013-11-03 21:30:12 7504 3 Response: 200 Type set to I
2013-11-03 21:30:12 7504 3 Command: PASV
2013-11-03 21:30:12 7504 3 Response: 227 Entering Passive Mode (192,168,217,20,136,49).
2013-11-03 21:30:12 7504 3 Status: Server sent passive reply with unroutable address. Using server address instead.
2013-11-03 21:30:12 7504 3 Command: MLSD
2013-11-03 21:30:32 7504 3 Error: Connection timed out
2013-11-03 21:30:32 7504 3 Error: Failed to retrieve directory listing

Any Ideas?

Have a great day,

Don