I thought I'd post that I've just put up a new SME 7.0 server and initially had loads of VPN problems. 80% of VPN connection attempts resulted in the old protocol not available message in the logs.
When the ADSL link went static IP and the speed moved from 256/64 to 512/128 all errors vanished. The server now has a 100% connection success rate. I believe it was the speed change that fixed it, not the change to a static as they happened a few days apart.
Is any exchange hardware altered during a speed change?
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While I'm here. Does anyone know how to stop Internet mail coming to the admin account.