FTP connectivity handling using PASV

[voicucosmin90]

I have the following case- data transfer under old FTP from iSeries to unix server and I have randomly issues related to the connectivity.
The login is completed with succes but when it tries to do put command it fails with different errors like unableto establish the connection or time out, even if the authentication was succesfully done.

I understood that with pasv I can handle this, as the issue is from the negotiation of the ports between the servers.
Can you tell me please how I need to use SENDPASV?
I need to have in the FTP script SENDPASV 0 or SENDPASV 1 before any cd, get, put, ls, dir commands?

[Brian Rusch]

You pretty much have it. Include the SENDPASV 1 command (which turns on passive mode) in your FTP script right after you log in to the FTP server.

[voicucosmin90]

Thanks Bryan!
so, SENDPASV 1 to be
Can you explain me shortly this? I have an overview but need to understand deeply.
many thanks!

[Brian Rusch]

I'm not sure what it is you need to understand. If it's the difference between active and passive mode FTP, there's a good explanation at this link: http://slacksite.com/other/ftp.html

[voicucosmin90]

Thanks Brian for the resource, I read right now.
wanted to understand the difference between sendpasv 0 and 1 and why sendpasv 1 will fix my connectivity issues for put commands