FTP linux client chokes on PASV

[David Jones_21]

My VMS 8.2 Alpha is running version TCPIP 5.5, I have a user who is having trouble with FTP from his linux PC (version unknown).

The user logs in and attempts a 'ls' command
and gets the response:
227 Entering Passive Mode (164,107,76,2,241,12)
ftp: connect: Invalid argument

I enabled the client activity log and all the TCPIP$FTP_SERVER.LOG file shows is multiple PASV commands. This problem appears to have developed when we upgraded from VMS 7.2-2, TCPIP 5.3.

[Peter Quodling]

Weren't there a bunch of Cert Security advisories on the use of PASV about a year or so ago.. finding the version of Linux, and possibly whether it has an ftp patches, would be a damn good start... Also consider turning on debug mode (-d) and packet trace mode (-t) from the client - may provide some insight...


q

[Peter Quodling]

The other thing that comes to mind, is...

have they tried SCP or SFTP? (the secure/SSH versions) - Do they suffer the same symptoms?

q

[Antoniov.]

Hi David,
before ls command, user can successfully any other ftp command?

Antonio Vigliotti

[David Jones_21]

More details. He says he's running Fedora Core 3 with patches up to date (2.6.12-1.1372_FC3). I used TCPTRACE to capture a session and it shows what the server and client logs show: session starts with a SYST
command followed by PASV commands (1 for each command tried) until a QUIT command closes the session.

My only guesses right now are that he is unknowingly running firewall software that blocks outbound connections or his client doesn't like that the 227 response ends in ')' rather than ').'.

[Antoniov.]

Where is the firewall?
PASV mode is usually used when ftp server is protected by firewall.
You must know if and where are firewall throught network.

Antonio Vigliotti

[John Altstatt · Accepted solution]

I have seen the exact same problem with the linux ftp client after upgrading the kernel
to FC3 2.6.12. Apparently something in the upgrade breaks ftp. A fresh build of NcFTP
works properly, as do lftp and gFTP. This is NOT a firewall problem, as the problem exists
when trying to ftp from servers on my local network.