I have a W2K3 domain with an E2K3 organisation. One of our E2K3 servers acts as a bridgehead server for internet email. I have configured primary, secondary and tertiary SMTP connectors for internet email. Each SMTP connector forwards to a different smart host, each SMTP connectors address space is for * domains with the cost for each ranging from 1 to 10 to 20.
In testing, when I prevent access to the smart host configured for the primary SMTP connector emails begin to queue on the primary SMTP connector. I was expecting that emails would automatically begin to route via the secondary SMTP connector.
Please can anyone advise on the steps necessary to configure multiple SMTP connectors for the same address space.
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There is no failover facility with Exchange 2003.
The most you can do is load balancing.
Exchange will try the lowest cost connector with the domain that matches. If that connect fails, then it will not try another. It will NDR the message back.
In short, the connectors with the higher cost will be ignored.
Simon.
Exchange will always use the lowest cost for the domain that matches.
The costs are simply to force email for a specific domain out a specific route.
In most cases this means you have two costs involved - a cost of 1 for specific domains and then 2 for the *.
However you could do something like co.uk on a cost of 2, example.co.uk on a cost of 1 and wildcard on cost of 3.
Simon.
It goes by the closest match.
Therefore if you have example.co.uk with a cost of 1 and co.uk with a cost of 2, and wildcard with a cost of 3, then all email to example.co.uk will use the first connector, everything else for co.uk will go out the second connector and all others out 3.
If you have two connectors with the cost of 1, (for example * and .co.uk) and then you send an email to example.co.uk then they will be load balanced, because they both match.
An email to example.com would only go out the *.
Costs have to be changed to control the email flow. Remember Exchange only routes email based on the recipient.
Simon.
Mestha
Your examples would use different connectors because of the domains being defined not because the cost is different. A more granular domain definition, x.co.uk being more granular than co.uk, results in that connector being favoured for email delivery to the x.co.uk domain. The cost in this instance is not relevant.
I am going to log a call with Microsoft to see if they know.
That is what I said.
Closest match.
The cost though is relevant.
If you have two connectors with the same cost and where the message can flow through both connectors, then both will be used.
You use a combination of cost and the domain to control the email going where you want it to.
For example, you could have two connectors, going in two different paths, for two separate domains, but with the same cost. That would result in the email going only via the specific connector.
However if you had two connectors, one with a specific domain and one with * on it and the cost was the same, then email for the specific domain will use both connectors because they both match.
Each email is evaluated individually. Therefore if there are two connectors with the same cost, which both could be used, then they will be load balanced.
If that didn't happen then cost would be irrelevant completely.
Simon.
I spoke with MS support. I have been advised not to use SMTP connectors with the same address space.
Exchange will first look at the address space. If it finds two connectors with the same address space it will only ever try to use the lowest cost connector, regardless of whether the associated smart host is available. Therefore the concept of costs for SMTP connectors is pointless in Exchange.
I was further advised that to provide a form of internet email resilience to Exchange multiple smart hosts can be defined on a single SMTP connector separated by semi colons. E.g. [10.88.0.23];[10.88.0.24];
However this is not guaranteed and you may see email using the other smart hosts even if the primary is available.
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by: AkhaterPosted on 2009-11-04 at 13:27:17ID: 25744129
As far as I know the "fail over" should happen if the SMTP server of the lower cost is not available not if it is rejecting the message.
how did you prevent access?