My Exchange server has stopped sending emails since my internet connection was changed and the external static IP address changed. Before the change my server was sending emails through my ISP's smarthost and even though my internet connection has changed I'm still with the same ISP so I kept the smarthost as it was but immediately I started getting bouncebacks saying there was a delay delivering my emails. These errors kept coming through throughout the day so I contacted the ISP who said they would create a reverse DNS record for my domain pointing to the new IP address so I deleted the SMTP smarthost in SBS console and told the server to send emails using DNS. This was done 6 hours ago and I still can't send emails so I ran the Remote Connectivity Analyzer for outgoing SMTP mail on my server which failed on the step "Attempting reverse DNS lookup for IP address: " then it gives my OLD external IP address. I've run the fix my network wizard and the Connect to Internet wizard, other than that I can't seem to find where I'm supposed to let Exchange know that my external IP address has changed, is this likely to be the problem?