Hi, we have an Exchange 2007 behind an ISA Server 2006. This ISA box have an IP1 used for normal browsing and another IP2 used for email. Rules were created normally using the wizards. Today we noticed two cases which some emails were stamped with IP1(browsing) instead of IP2 (email); because we use SPF records in the Internet to only allow outbound email from IP2, the mails were rejected. Addtionally, ISA Server only allows SMTP traffic from the Exchange server and denies it to other internal hosts.
I have checked the internal DNS configuration with AD and the internal MX record is fine. Our ISP checked the external MX record and it is fine too.
So, my question is why Exchange is stamping the email with this IP1?.