ftpd 425 Can't build data connection

[Charles_11]

We have a ftp server with 100's of users that all connect and work without trouble. Once in a while (every 6 months or so) we get a new user who get's the following errors

Can't build data connection: Connection timed out, when the try to put/get. If they try to put a file, a zero byte file is created.
Currently this user is coming from a SCO box, sometimes it occurs with NT/2000.

I've heard this message has to do with passive/active mode.

Thanks Charlie

[Rita C Workman]

Question:

Are you using anything like SecureCRT??

/rcw

[Paul Sperry]

This may help
http://forums.itrc.hp.com/cm/QuestionAnswer/1,,0x17510fe6d0f7d61190050090279cd0f9,00.html

[Rita C Workman]

The post above sends you to a thread that points to what I think is your issue.

If you have a client that may be behind a firewall...coming to your server that is behind a firewall...well there's a lot of tunneling going on there. It may very well be that all the ports (as Shannon mentioned above) have not been listed in your firewall appropriately. The remaining concern here may be just how much you are opening up your firewalls.

Just a thought,
Rita

[rick jones]

The zero byte file on put is presumeably because the FTP server creates the file before the data connection completes.

You might check the syslog for logging messages from the ftpd. When I was doing some of my first FTP server performance writeups, I ran into a situation where FTP wasn't setting some options it should and that led to data connections not being established. Since then that has been fixed in the ftpd - of course if you are running really old bits (we can't tell since you didn't say... :) still being on the latest patches might be goodness.