Exchange 2007 as Backup MX for another 2007 exchange in a different forest

i have an exchange 2007 server in location A in forest a.local.  I have another exchange 2007 server in location B in forest b.local.  There is a VPN and trust relationship between the domains but I probably dont need to use it.  how can I use each server to be a backup mx server for the other.  I understand the DNS settings on the email domains, but I'm not sure how to configure the exchange servers.

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"I understand the DNS settings on the email domains, but I'm not sure how to configure the exchange servers."
Well all you have to do it add on two MX records for each domain and give them different priority. Also you would need to add both the domain names as authorized in your recieve connectors.
What is the namespace that you are using to recieve mail from outside?
Mahmoud SabrySenior IT Systems EngineerCommented:
for Domain A
configure internal relay domain from accepted domains tab for Domain B(will be external relay domain if you will route emails through edge server )
 second for domain A also
create a new send connector as an "internal" ,and in the address space tab add domain B domainname in it, and in the route email to the following smart host add the IP address of Internal IP for DomainB HUB/Edge server
third for domain B
add a new MX record with lower priority (larger value) that points to Real IP address for Domain_A Edge/Hub server

do the same scenario for domainB and the MX record for domain A

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jdroger2Author Commented:
Thanks Hila, I'm going to try this out this week and I'll post back
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jdroger2Author Commented:
oops I meant msabry006 :)
Mahmoud SabrySenior IT Systems EngineerCommented:
what is the result?
jdroger2Author Commented:
Thanks msabry006, that looks like what we needed.
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