Hi, we use the Postini for our MX records. Now, we have external web site which use the web hosts' SMTP server that users requested the info. Users fill form and the form request will be send to my several external account (like gmail) or my email address@mycompany.com. I can receive mails with external email address but I can not receive mails for my email address @mycompany.com But, we whitelist this IP on the Postini device. Are there more configs I need to set up since we already whitelist? Thank you.

This would appear to be completely unrelated to Exchange in any shape or form... surely you should be asking Postini. However you may have to speak to the hosting company. Many hosts will setup their network to presume that they are responsible for all services for a domain, including email. Therefore your email may not even be leaving their network as it is being routed to one of their own servers internally. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources | In the UK? Hire Me.