exchange 2007: hub transport authentication settings
in the exchange management console
server configuration->hub transport->select hub transport server
then double-click client <server name> under receive connectors
relevant info in the network, authentication, and permission groups tabs
common settings…
server name: hub transport FQDN
port: 587
security: STARTTLS
auth method: password
source:
http://help.globalscape.com/help/me3/configuring_authenticated_access_to_exchange.htm