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Old 08-10-2002, 02:06 PM   #1
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Default help with transfering to friend

hi well i am trying to transfer a file to my friend using fxp . so i am fxping from one place to another heh go figure. and i consistently get this error

425 Cannot open data connection.

and it works without a router but since i got my router just recently i have been unable to determine what to do. any help is great thanx
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Old 08-10-2002, 02:36 PM   #2
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Join Date: Oct 2001
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Many routers are not compatible with FXP because they use NAT (Network Address Translations)

NAT provides protocol helpers which monitor known protocols and corrects any mistakes made by by the users software.

For example on a basic LAN w/ router you may have a network IP of and a external IP of To all of the applications on your system your IP is

When performing basic FTP commands the client may send the PORT command which is your IP ( followed by the port, behind a router this IP would be incorrect, and when performing a FXP transfer PORT uses the IP of the other FTP server.

Now NAT automatically changes the IP to match your external IP, which in turn breaks FXP.

Normally NAT only monitors port 21 for the FTP protocol so running the FTP servers on a non-standard port (i.e. 245) should eliminate the problem.
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Old 08-11-2002, 02:00 PM   #3
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On my router configuration page I have an option labeled "Use non-standard FTP port [____]". Finally I know what this is for
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abor, data, friend, router, works

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