- Internal messages always go for shortest route available
- A connector will be considered off ONLY when all bridgehead server(s) on that connector are down
- For external messages, a route is chosen with closest SMTP name space matching first regardless the cost. For example, an email destined to *.net will go to connector that is responsible for *.net even it has higher cost than the one that is responsible for * space.
- Routing does not fail over from a connector with a specific address space to a connector with a less specific space. So when there is problem with all *.net connector(s), emails will be queued up in *.net connector(s)
- The above 2 rules don’t apply to user who doesn’t have permission to the specific connector. Consider connector that a user doesn’t have permission as non-exist when routing his emails.