I prefer using the module-group Net::LDAP (called perl-ldap on CPAN or Activestate).

You can connect to Exchange like to any other LDAP-Server about in the following way:

use Net::LDAP;
use Net::LDAP::Util qw(ldap_error_text ldap_error_name);

# adapt the following variables to your exchange-Server
my $server = "192.168.0.1"; # or hostname
my $port = 389;
my $user = "cn=username,cn=Recipients,ou=Location,o=Company";
my $password = "topSecret";
my $version = 3;

# connect to server
my $c = Net::LDAP->new($server, port=>$port);
die "Error: couldn't connect: $@\n" unless ($c){

# try to bind as user    
my $mesg = $c->bind( $user, password => $password, 
                     version => $version);

if ($mesg->code()){ # on error
    # get errormessages
    my $errorCode = $mesg->code;
    my $errorText = ldap_error_text($mesg->code);
    my $errorMsg  = ldap_error_name($mesg->code);

    $c->Disconnect();
    
    die <<EOD;

Error in bind: 
 Code: $errorCode
 Message: $errorMsg
 Text: $errorText

EOD
    ;
[download]

Best regards,
perl -le "s==*F=e=>y~\*martinF~stronat~=>s~[^\w]~~g=>chop,print"

LDAP is a directory access protocol, not a mail protocol. You'd probably have better luck using IMAP or POP3 (presuming that your M$ admins have turned that on). See Net::IMAP or Net::POP3.