I have a Watchguard Firebox 1000 and I want to send my outgoing SMTP mail to the MessageLabs server for virus scanning. The firewall's outgoing SMTP traffic is currently configured from our Exchange 5.5 Server's IP address to Any. I updated the To: address from any to the MessageLabs server's IP address that they gave me. I checked my Exchange Server's outbound queue and the e-mail won't go out after I make this change. The details show host unreachable.