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I have an Exchange 2010 infrastructure with multiple Hub servers and multiple Edge servers; all Edge servers are subscribed to the organization and are used to deliver both inbound and outbound messages.

I need to perform some pretty invasive maintenance on the Edge servers (full O.S. patching, Exchange SP2, FPE rollup, etc.), so I'd like to remove each of them from the mail flow, get it in shape and then put it back. But I also want it to deliver all messages which have been submitted to it, without losing any of them.

Removing the server from the inbound mail flow is as trivial as deleting its MX record from the public DNS; what I'm looking for is a way to remove it from the outbound mail flow: I want the hub servers to send outbound messages only to the other servers, not to the one I'm currently working on.

The following solutions don't work:

  • Removing the Edge subscription: the server is rendered unable to send anything to the Hub servers, including NDRs; also, this causes Shadow Redundancy to kick in and re-send all messages queued on the removed server, causing message duplication; definitely not what I want.
  • Removing the server as a source server for the outbound Send Connector: this causes the still-queued messages on the Edge server to not be delivered, because the server loses its outbound route for them.
  • Disable the Receive Connector on the Edge server: this also causes Shadow Redundancy to kick in, because the Hub servers can't poll the Edge server for delivery acknowledgements.

I know there is a hidden Send Connector which tells Exchange how to route outbound messages to Edge servers; this is what I would need to configure. But I can't find a way to get my hands on it.

How can I bypass a specific Edge server and only have Exchange send outbound messages through the other one(s)?

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As there are more then one edge server I assume they are network balanced so there is no need to disable anything. Stop exchange services on one Edge Server, do maintenance and reboot, then go on with the next.

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This will cause Shadow Redundancy to kick in if the server is unreachable for more than three hours. We don't want duplicate messages. – Massimo May 2 '12 at 14:46
Also, Edge servers are not load-balanced... they are all subscribed to the Exchange organization. – Massimo May 2 '12 at 14:50
Edge servers can be load balanced inbound (SMTP) by creating two DNS MX records with the same priority. Also "If more than one Edge Transport server is subscribed to the same Active Directory site, additional Send connectors to the Internet aren't created. Instead, all Edge Subscriptions are added to the same Send connector as source servers. This configuration causes outbound connections to the Internet to be load balanced between the subscribed Edge Transport servers." – Danilo Brambilla May 2 '12 at 19:34
I'm talking about outbound messages. The one sent from Hub servers to Edge servers, and then from Edge servers to the Internet. There's no MX record or load balancing involved in this process. – Massimo May 2 '12 at 20:03

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