#!/usr/bin/perl -l

use strict;
use Net::SFTP;

my ( $host, $user, $pass ) = ( ... );

my $sftp = Net::SFTP->new( $host, 
    user => $user, password => $pass, 
    ssh_args => [ debug => 1 ] );

##</code><code>##

%perl sftp_test.pl
 Reading configuration data /usr/home/*****/.ssh/config
 Reading configuration data /etc/ssh_config
 Connecting to *************, port 22.
 Remote version string: SSH-2.0-VShell_2_3_1_151 VShell
 Remote protocol version 2.0, remote software version VShell_2_3_1_151 VShell
 Net::SSH::Perl Version 1.30, protocol version 2.0.
 No compat match: VShell_2_3_1_151 VShell
 Connection established.
 Sent key-exchange init (KEXINIT), wait response.
 Algorithms, c->s: 3des-cbc hmac-sha1 none
 Algorithms, s->c: 3des-cbc hmac-sha1 none
 Entering Diffie-Hellman Group 1 key exchange.
 Sent DH public key, waiting for reply.
Received disconnect message: Invalid packet header.  This probably indicates a problem with key exchange or encryption. at /usr/local/lib/perl5/site_perl/5.8.4/Net/SSH/Perl/Kex/DH1.pm line 41