Hi all,In our company we have one mail server exchange 2007 with all roles on it, and two ISA 2006 Standard connected to two different providers. In first ISA, we have published Mail Server in public DNS, like: mail.domain.com to its Public IP address, and mail2.domain.com to pubilc IP address connected to second ISA from second provider.Now, If one fails we have to change default gateway in exchange server, and route mails through that one. However, users who want to connect through OWA, or ActiveSync, they have to know the second address mail2.domain.com.My question is: can we write 2 default gateways to Exchange, and keep it able to send, and receive emails through whichever IPS it finds easer (based on cost on MX record in Public DNS), or can it cause any problem?Is there any way for OWA, and ActiveSync to work with same address, regardless which provider is up.Thank you

I think that is something do over DMZ side. called as load balancingVinod |CCNA|MCSE 2003 +Messaging|MCTS|ITIL V3|

Is it problem if we use two Default Gateways in the same time, at least mails sending,and receiving to work.

Hi,Exchange 2007's send connector could not be switched to next if one of the send connector is unavailable until change it manually.Thus, you can create only one send connector and set the two default gateways as the smart host to achieve the Fault Tolerance.For the receiving email, you can create the two MX records in the public DNS, then set different costs for the two MX records. When the first lower cost MX record is not available, the second MX record will be used.To load balancing for OWA and ActiveSync, you can use the third party device to achieve this goal. Such as the F5.ThanksAllen

Allen,Thank you for your reply.Right now, default gateway of Exchange is ISA1, it uses mail.domain.com in public DNS, and it works OK. If link in ISA1, goes down, we change default gateway of Exchange to ISA2, and it uses mail2.domain.com in public DNS, and again send/receive goes fine.Now if we put two default GW, and both are online, will it confuse Exchange in the long term while sending mails out, or it will work just fine.

Hi,It will work just fine. When you specify more than one smart hosts on a connector, load balancing is achieved in a round robin manner by distributing connections across the smart hosts. Fault tolerance is achieved by failing over to the next alternative smart host when the previously attempted smart host is unavailable for that connector.ThanksAllen