
Part III: Working with PowerShell in a Production Environment
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Route selection uses an algorithm to match valid connectors against all connectors in the organization
except Routing Connectors, until a single path is left. If no paths are left after running through the pro-
cess, recipients are marked as unreachable or a non - delivery report (NDR) is generated. The algorithm is
based on the following:
Connector scope
Target address space
Connector restrictions
The path with the lowest cost from source to destination, with the preference to stay within the
Exchange Server 2007 routing group as long as possible
The path with the least number of hops
The first site alphanumerically sorted
The destination address is a combination of delivery type and domain. For example, sending a mail to
Jeffrey.Rosen@chicago.exchangeexchange.com has a delivery type of SMTP, and a destination
domain
exchangeexchange.com . Exchange routing always tries to find the best match, which is
defined by the number of characters that match to the address space configured on the connector. This
concept is shown in the following table. The best match is
Chicago.exchangeexchange.com .
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❑
❑
❑
❑
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Address Space Count
*.exchangeexchange.com 21
Chicago.exchangeexchange.com 28
Exchangeexchange.com
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During processing, the Hub Transport decides on the message routing. By default, the site link cost asso- ...