ftp ftp.glb.xyz.net
Connected to ftp.glb.xyz.net
220-Firewall ftp proxy.  You must login to the proxy first.
220 Username:
User (ftp.glb.xyz.net:(none)): <proxy_user>
331 Password: <proxy_pass>
230-Proxy authentication successful.  Connecting to the server...
230-Firewall ftp proxy.  You must login to the proxy first.
230 Please use the 'user' command to login to the FTP server.
ftp> user <ftp_user>@remote-ftpsite.com
331-ftp1pdmz8 NcFTPd Server (licensed copy) ready.
331-
331 User <ftp_user> okay, need password.
Password: <ftp_pass>
230-You are user #251 of 1000 simultaneous users allowed.
230 Restricted user logged in.
=================== 

To accomplish this in Perl, we did the below: 

my $ftp = Net::FTP->new(‘remote-ftpsite.com’,   Firewall => ftp.glb.xyz.net',   FirewallType => 7,  Debug => 1 );
$ftp->authorize($proxy_user , $proxy_pass); 
my $ret = $ftp->login($ftp_user, $ftp_pass);
========================

But we are getting below error:
 
Net::FTP>>> Net::FTP(2.75)
Net::FTP>>>   Exporter(5.57)
Net::FTP>>>   Net::Cmd(2.26)
Net::FTP>>>   IO::Socket::INET(1.27)
Net::FTP>>>     IO::Socket(1.28)
Net::FTP>>>       IO::Handle(1.23)
Net::FTP=GLOB(0x2c640ffc)<<< 220-Firewall ftp proxy.  You must login to the proxy first.
Net::FTP=GLOB(0x2c640ffc)<<< 220 Username:
Net::FTP=GLOB(0x2c640ffc)>>> AUTH <proxy_user>
Net::FTP=GLOB(0x2c640ffc)<<< 530 Please log in with USER.
Net::FTP=GLOB(0x2c640ffc)>>> user <ftp_user>@remote-ftpsite.com
Net::FTP=GLOB(0x2c640ffc)<<< 331 Password:
Net::FTP=GLOB(0x2c640ffc)>>> PASS ....
Net::FTP=GLOB(0x2c640ffc)<<< 421 Proxy authentication failure.
19:24:03 Feed: 'BLOOMBERG' Error:  Unable to connect to @remote-ftpsite.com

============================== 

It seems that it issued the User command correctly as expected:    

User <ftp_user>@remote_ftpsite.com (which works fine from command prompt)

But not sure why it’s failing. Tried with the other Firewall types as well (just in case), but no luck.
Any help will be greatly appreciated.