for (lalala...) {
    eval {
        my $session = Net::Telnet::Cisco->new(Host => '$Geraet');
        $session->login('login', 'password');
        my @output = $session->cmd('show version'); 
        print @output; 
        $session->close; 
    }
    print "Da is was schief gelaufen: $@\n" if $@;
}