Why can not sent file by ftp from the cmd client?

Hello at work recently there was such problem:
Every day after the completion of the backup operation, the workstations send the xml report result to an ftp server on the Internet. The script looks like this:
lcd C:\temp\
open ftp.myserver.com
login
password

mput nrobot_OAK_2016-09-21T08-06-57Z(-6).xml

bye
This script is executed in multiple branches. But a few branches at some point stopped sending the reports. I tried to start the dispatch manually, and this is what is output to stdout:
ftp> ftp>Connection with ftp.myserver.com
open ftp.myserver.com
220 Microsoft FTP Service
User (ftp.myserver.com:(none)): 
331 Password required

230 User logged in.

ftp> ftp> 
mput nrobot_OAK_2016-09-21T08-06-57Z(-6).xml
mput nrobot_OAK_2016-09-21T08-06-57Z(-6).xml? 
200 PORT command successful.
150 Opening ASCII mode data connection.
By process of elimination I assumed that the problem could be at ISP level because it is the same on the problematic branches. But the support answered that they were all right.
Here is the stdout from the working branch:
ftp> ftp>Connection with ftp.myserver.com
open ftp.myserver.com
220 Microsoft FTP Service
User (ftp.myserver.com:(none)): 
331 Password required

230 User logged in.

ftp> mput nrobot_OAK_2016-09-21T08-06-57Z(-6).xml
mput nrobot_OAK_2016-09-21T08-06-57Z(-6).xml? 
200 PORT command successful.
125 Data connection already open; Transfer starting.
226 Transfer complete.
ftp: 30250 bytes sent in 0.13 (sec) with speed 232.69 (KB/sec).
ftp> bye
221 Goodbye.

Here is a screenshot of packet capture in Wireshark with the problem of the branch:
5223549ef5dd4e548d0a849f853efdae.png
Here is a screenshot of packet capture in Wireshark with the branch where there are no problems:
6c3a38ed955b47faa55f5f861b04448e.png

Why do I believe that the problem is on the ISP level ? Because I came on the problem branch with 3G modem MTS and performed a report through the modem, no problems. Still have to say that if you view directories on the FTP server through the browser, then the problem also does not arise.

Please help me understand.
July 4th 19 at 22:48
1 answer
July 4th 19 at 22:50
Solution
The connection you have on port 21 the server has been established. Further not set the session data transmission.
FTP.exe uses active mode, and third-party clients use passive. Problem or Brandywine on the server or client(disable/open check). Or provider does not give a connection to the IP of your server on port 20
I had the same thought as you, but brandmauer have to disabled on all machines via GPO, and change the ISP as I wrote the question decided. The idea is in the active mode, the client needs to send PORT command to the server, but for some reason, in wireshark I don't see it. - Linnie_Armstrong commented on July 4th 19 at 22:53
A Request: PORT 10, 216,55,19,163,68 is that the client sends ? - Linnie_Armstrong commented on July 4th 19 at 22:56
In active mode the client tells the server the port is listening and the server initiates a session from port 20 to this port. If the other points you have active mode on the same server is running, either on the side of the problematic client SIP locit outside traffic on port 20 - Alexander.Brek commented on July 4th 19 at 22:59
What kind of SIP is it? I only know about SIP in the context of voip. And can you please answer my question, where in wireshark shows that the client on which port it is possible to initiate a connection? - Linnie_Armstrong commented on July 4th 19 at 23:02
And probably the ISP and not SIP ))) - Linnie_Armstrong commented on July 4th 19 at 23:05
A typo, ISP. The answer to your question: [Request PORT] the IP:port. In both of your dumps - Alexander.Brek commented on July 4th 19 at 23:08

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