I've checked your test case lib525.c. It also hangs after PORT is send:

* About to connect() to localhost port 21 (#0)
* Trying 127.0.0.1... * Connected to localhost (127.0.0.1) port 21 (#0)
< 220-Microsoft FTP Service
< 220 Banner
> USER anonymous
< 331 Anonymous access allowed, send identity (e-mail name) as password.
> PASS curl_by_daniel_at_haxx.se
< 230-Welcome
< 230 Anonymous user logged in.
> PWD
< 257 "/" is current directory.
* Entry path is '/'
* Telling server to connect to 127.0.0.1:3905
> PORT 127,0,0,1,15,65
< 200 PORT command successful.
* Connect data stream actively
* Connection time-out after 301000 ms
* Connection #0 to host localhost left intact
Press any key to continue

To run on Win platform I modified lib525.c a little bit.
Please have a look at the attached file.

BTW: did you run your test suite on some of Win platforms?

Best regards,
Alexey Simak

----- Original Message -----
From: "Alexey Simak" <alexeysimak_at_gmail.com>
To: <curl-library_at_cool.haxx.se>
Sent: Wednesday, November 22, 2006 5:15 PM
Subject: Re: [ curl-Bugs-1600447 ] Active FTP upload/download with
multiinterface.

> Hi,
>
> Thanks for quick response! Please have a look at my comments below.
>
> > That particular problem was fixed, as you can see in that thread.
> As far as I understood there were some strange things which were not
> explained
> (http://curl.haxx.se/mail/lib-2006-06/0055.html):
> ...
> strange thing...
> the lib525 tool against a localhost ProFTPD (1.2.10) on debian
stable
> also works for me,
> but not to a remote one (legolas: ProFTPD 1.2.10 - debian stable).
> ...
>
> > What does it mean when a "process hangs up" ? You mean that it hangs
(for
> a
> > long time)?
> Yes, I mean that it hangs untill connection timeout expires. Here is the
> complete output:
> * About to connect() to ftp.sunet.se port 21 (#0)
> * Trying 194.71.11.70... * Connected to ftp.sunet.se
> (194.71.11.70) port 21 (#
> 0)
> < 220 Welcome to ftp.sunet.se
> > USER anonymous
> < 331 Any password will work
> > PASS curl_by_daniel_at_haxx.se
> < 230 Any password will work
> > PWD
> < 257 "/" is your current location
> * Entry path is '/'
> > CWD pub
> < 250 OK. Current directory is /pub
> > CWD www
> < 250 OK. Current directory is /pub/www
> > CWD utilities
> < 250 OK. Current directory is /pub/www/utilities
> > CWD curl
> < 250 OK. Current directory is /pub/www/utilities/curl
> * Telling server to connect to 85.202.18.127:2221
> > PORT 85,202,18,127,8,173
> < 200 PORT command successful
> * Connect data stream actively
> * Connection time-out after 300219 ms
> * Remembering we are in dir pub/www/utilities/curl/
> * Connection #0 to host ftp.sunet.se left intact
> Press any key to continue
>
> >Can you please show us that change with diff -u?
> --- multi.c 2006-11-22 16:18:26.000000000 +0200
> +++ multi-fixed.c 2006-11-21 17:07:34.000000000 +0200
> @@ -1057,11 +1057,14 @@
> break;
>
> case CURLM_STATE_DO_MORE:
> - /* Ready to do more? */
> - easy->result = Curl_is_connected(easy->easy_conn,
> - SECONDARYSOCKET,
> - &connected);
> - if(connected) {
> + if(!easy->easy_conn->data->set.ftp_use_port) {
> + /* Ready to do more? */
> + easy->result = Curl_is_connected(easy->easy_conn,
> + SECONDARYSOCKET,
> + &connected);
> + }
> +
> + if(connected || easy->easy_conn->data->set.ftp_use_port ) {
> /*
> * When we are connected, DO MORE and then go DO_DONE
> */
>
> > Are you saying that your server(s) are not connecting to the client
after
> STOR
> > is sent?
> No, FTP server is connecting to the client after STOR or RETR is sent.
> The problem is that client does not send STOR or RETR after PORT
> (as shown in the output above).
>
>
> > Aren't we already doing FTP PORT nicely in the test suite? Why does it
> work
> > there and not for you?
> I will check your test case for active FTP mode( lib525.c - right ? ) and
> inform you about results a bit later.
>
> Thanks,
> Alexey Simak
>