Have a configuration of Exchange 2000 Server for workgroup mail only, seperate local Pop3 Mail Server for Internet mail, and MS Outlook 2000 clients and experiencing intermittant problems sending internet mail. Could send internet mail to someone today with not problems however, if I trying sending it tomorrow, mail may bounce back (very sporadic). May recieve an undeliverable statement 2 days later. Local Pop3 mail server functions fine if you use a generic pop3 client to send messages to same email addresses. Selected different choices in MS Outlook, who processes mail for delivery, (Exchange or local POP3 server) but same issues. Same combo has been working fine with Exchange 5.5 for years. Problem started when Exchange 2000 was inserted into the picture.