On 2015-01-08 03:19, Sampsa Laine wrote: On 8 Jan 2015, at 04:03, Johnny Billquist <bqt at softjar.se> wrote: Thanks. (I doubt the VMS ftp server would care about NAT, it's not something the system behind a NAT knows or should care about. It's the NAT router who have to do all the work...) IIRC unless the FTP server is working is "Passive Mode" port 21 is used just for control, and the server opens a random high-numbered port to which the client connects and the data is transferred over that - so that's where NAT'ing gets in the way. Almost. In active mode, the ftp server initiates a second connection for data. This is by default on port 20 of the server, and by default to the same port as the control connection of the client. And the client is expected to listen for this specific connection. However, NAT boxes normally knows this, and actually handles all needed for it to work. I have no need for FTP on my boxes (I prefer Kermit) so haven't tried particularly hard to get around this problem. :-) Well, if your NAT box do something funny, then I'd just go for passive mode, which have a higher chance of working, since in that case, the client also opens the data connection. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol