I was having a major headache with Net::FTP recently on my raspberry pi. I found that this code:

use Net::FTP;

$ftp = Net::FTP->new("xxx", Debug => 1)
    or die "Cannot connect to host: $@";
    
$ftp->login("xxx",'xxx')
      or die "Cannot login ", $ftp->message;
    
$ftp->cwd("xxx")
      or die "Cannot change working directory ", $ftp->message;
      
$ftp->put("test.txt")
      or die "put failed ", $ftp->message;

$ftp->quit;
[download]

Didn't work and I got the error: 502 'PORT' command not implemented. I tried this on both Raspbian and Arch Arm. The same code worked fine from a windows box, however. On windows, I noticed that put behaved differently, putting the connection into PASV mode before transferring the file. On linux this didn't happen. I solved the issue by putting the entire connection into PASV mode (calling pasv() before put() didn't work):

$ftp = Net::FTP->new("xxx", Debug => 1, Passive => 1)
    or die "Cannot connect to host: $@";
[download]

This worked fine. Just putting this here in case someone else has the issue!