No pty allocated, pty required..

Use use_pty => 1 in the constructor; also, the customer server expects SSH2, so use protocol => 2 in the constructor also. Here's the way that I would do it:

#!/usr/bin/perl

use strict;
use warnings;
use Net::SSH::Perl;

my $user = 'user';
my $pass = 'password';
my $cmd  = "ls /root";

my $ssh = Net::SSH::Perl->new('localhost',
    debug    => 1,
    protocol => 2,
    use_pty  => 1,
);
    
$ssh->login($user, $pass) ;

if ($cmd) {
    my($stdout, $stderr, $exit) = $ssh->cmd($cmd);
    print $stdout if $stdout;
    print $stderr if $stderr;
}
else {
    eval "use Term::ReadKey;";
    ReadMode('raw');
    eval "END { ReadMode('restore') };";
    $ssh->shell;
    print "Connection to host closed.\n";
}

__END__
[download]

Is there an option to send commands and collect output when using $ssh->shell interactive mode?

I think this is the only way I'll success since customer node is not a standard Linux box

Anyway, this is the output when I run the code above:

sem1: Reading configuration data /root/.ssh/config
sem1: Reading configuration data /etc/ssh_config
sem1: Allocated local port 1023.
sem1: Connecting to 1.1.1.1, port 22.
sem1: Remote protocol version 2.0, remote software version OpenSSH_4.3
+-40020723001500
sem1: Net::SSH::Perl Version 1.33, protocol version 2.0.
sem1: No compat match: OpenSSH_4.3-40020723001500.
sem1: Connection established.
sem1: Sent key-exchange init (KEXINIT), wait response.
sem1: Algorithms, c->s: 3des-cbc hmac-sha1 none
sem1: Algorithms, s->c: 3des-cbc hmac-sha1 none
sem1: Entering Diffie-Hellman Group 1 key exchange.
sem1: Sent DH public key, waiting for reply.
sem1: Received host key, type 'ssh-dss'.
sem1: Host '1.1.1.1' is known and matches the host key.
sem1: Computing shared secret key.
sem1: Verifying server signature.
sem1: Waiting for NEWKEYS message.
sem1: Enabling incoming encryption/MAC/compression.
sem1: Send NEWKEYS, enable outgoing encryption/MAC/compression.
sem1: Sending request for user-authentication service.
sem1: Service accepted: ssh-userauth.
sem1: Trying empty user-authentication request.
sem1: Authentication methods that can continue: password.
sem1: Next method to try is password.
sem1: Trying password authentication.
sem1: Login completed, opening dummy shell channel.
sem1: channel 0: new [client-session]
sem1: Requesting channel_open for channel 0.
sem1: channel 0: open confirm rwindow 0 rmax 32768
sem1: Got channel open confirmation, requesting shell.
sem1: Requesting service shell on channel 0.
sem1: channel 1: new [client-session]
sem1: Requesting channel_open for channel 1.
sem1: Entering interactive session.
Received disconnect message: No pty allocated, pty required with Telne
+t SSH
at /usr/cti/apps/CSPbase/Perl/lib/perl5/site_perl/5.8.8/Net/SSH/Perl/S
+SH2.pm line 300
[download]

Try adding set_interactive to the constructor.