FTP Fiddling
Apr. 22nd, 2004 07:54 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
major_clangerAnyone have any idea why I might be having problems ftp'ing files from my iBook to my filespace on Cix?
I wanted to upload some pics to link to them from LJ and as this was the first time I'd done this from my Mac I found a simple ftp client (Transmit) that would, it seemed, do the job for me.
Well, I could log in to Cix and view my existing files, but every attempt to upload ended with the transfer stalling and a zero-size file being created at the far end.
I then tried the UNIX command-line ftp. Exactly the same result.
I've checked my router firewall settings, and it is configured to allow all outgoing services. As for the OSX firewall, as I understand it the 'ftp' setting is for incoming services, not outgoing.
So what am I missing?
MC
I wanted to upload some pics to link to them from LJ and as this was the first time I'd done this from my Mac I found a simple ftp client (Transmit) that would, it seemed, do the job for me.
Well, I could log in to Cix and view my existing files, but every attempt to upload ended with the transfer stalling and a zero-size file being created at the far end.
I then tried the UNIX command-line ftp. Exactly the same result.
I've checked my router firewall settings, and it is configured to allow all outgoing services. As for the OSX firewall, as I understand it the 'ftp' setting is for incoming services, not outgoing.
So what am I missing?
MC
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no subject
Date: 2004-04-22 12:59 pm (UTC)When you connect to a site via FTP, you are opening a control channel. Commands to change directory, list files, etc, all go through the control channel. But for actual file transfers, FTP (the protocol) specified that a separate active connection initiated from the server end should be established (so that control over the session could be maintained via the control channel even while a file transfer was occuring over the data channel). Obviously, if a server tries to open a separate socket to your laptop the firewall is going to block it.
To deal with this problem, FTP also permits "passive" connections, in which the data is sent via the control channel. In the command line FTP client, you can use the -p command line flag (at least, the OS/X version of ftp(1) supports this). Or hunt for a suitable setting in your GUI program.
One thing gives me cause for concern: the OS/X command line FTP client defaults to passive connections these days, by design. This bears some digging ...