I have Exchange 5.5 SP 2. I am also using Internet Mail Service. My internet email has been working fine. All of the sudden I cant receive email that comes from an IP address. If it comes from a resolved name it comes in fine. I turned on SMTP logging and I can see where it says A connection was accepted from xxx.xxx.xxx.xxx. Then nothing happens. When it comes from a resolved name it says a connection was accepted from xxx.yyyyyy.com and I can see the whole email transaction. Any ideas? Thanks in advance.