Data Loss Prevention Network Prevent for Email
Email is processing very slow when using MS Exchange 2010 MTAs
Messages seen in RequestProcessor log:
[Severe] (SMTP_CONNECTION .5204] Peer disconnected unexpectedly...reason=End of stream
If an Exchange 2010 transport server receives messages from a previous version of Exchange Server or a non-Exchange source, Exchange attempts to achieve shadow redundancy by delaying the acknowledgement to the sending server until it verifies that the message has been successfully delivered to all next hops internally.
The delayed acknowledgement time-out is controlled by the MaxAcknowledgementDelay attribute of each Receive connector. The default value is 30 seconds.
Review the DotTimeInMs for each message in the RequestProcessor log on the Email Prevent server. If it is close to 30000 Ms, then this may be the cause.
DLP Email Prevent is configured in Forwarding mode.
MS Exchange 2010 email server
MS Exchange Edge 2010 email gateway
Setting the MaxAcknowledgementDelay attribute to 0 seconds and restarting the Exchange services removes the delay and messages are received immediately by the downstream MTA.