A network guy trying to solve a mail problem here...Here is the situation.I need to have a Microsoft Exchange server point to an alternate DNS server when it has to send a mail to a specific zone, and use its default DNS server for everything else.For example,The exchange server has to point to aprivate DNS server when it needs to resolve the MX record for aaa.com. For everything else, it can use its default configured DNS server.The problem stems from integrating sites. We are trying to connect a private line to various companies and one of the services we want is to send email through that private line.Lets say we are called sitea.com and they are called siteb.com. If I send a mail out to siteb.com, we want it going out to the private line, pointing to SiteB's internally known mail servers IP address. If for any reason that line isnt available, we would want it going out to the internet as a backup line.Of course we can create a manual entry on the mail server itself to say if Im sending mail out to siteb.com, then send it to x.x.x.x and NOT go to the DNS server for the MX record. However, this doesnt give me the backup to the internet option. Zone transfers also doesnt work, since I will be translating their mail server IP addressthrough the private connection due to IP address conflict issues.I am looking to create a DNS server dedicated for my mail server which then I can point the mail server to when sending mail to siteb.com. This DNS zone will have 2 MX entry primary being the internal IP address and the backup being the internet known IP address.I know I can do this with Ironport. Does Exchange have a method of doing this?

Hey Network Guy, Hope this response makes sense to you. I personally wouldn't touch DNS in order to resolve your problem. Exchange has to ability to recognize multiple paths to an e-mail destination via the use of connectors. Depending on the version of Exchange that you're using, you can deploy either two SMTP Connectors (Exchange 2000/2003) or two Send Connectors (Exchange 2007) to the same destination Email domain name (ie "*.siteb.com" and define various costs on each connector to define a preferred path for the Exchange server to the destination. Using the "Route all mail through the following smart hosts " option, you can define an IP Address in each connector that corresponds to either the Private or Public IP addresses of the remote Email Server. Here's a link on how to do it in Exchange 2003: http://www.msexchange.org/tutorials/Configuring-SMTP-Connector.html and one for Exchange 2007: http://technet.microsoft.com/en-us/library/aa998814.aspx Ook

Hi, I think that the method to create two SMTP connector in Exchange 2003 is available. The Exchange will fail over to the next connector if the Smart host of the first SMTP connector is down. Nevertheless, create two Send Connector in Exchange 2007 is not available as the Exchange 2007 does have LinkState table anymore. The Exchange 2007 will not be able to know the Smart host of the first Send connector is down. Therefore, it will not failover to next Send Connector. The message will stuck in the queue until Admin make a change manually. For your reference: http://social.technet.microsoft.com/forums/en-US/exchangesvrtransport/thread/2dd0280a-6588-46b2-b49e-331fd50c2680/ Would you please let me know how you configure your DNS server. Whether you configure the Exchange Server to use a Public DNS directly. If I am right, I suggest you have the Exchange Server to user internal DNS server. Then, create a zone for the specific domain. For other domains, you can have the internal DNS server to forward the request to external DNS server. Configuring Transport Server Properties http://technet.microsoft.com/en-us/library/aa997166.aspx Mike