Anyone seen this issue before.
When you have two SM (13.3 Ent) servers both configured with Jumbo Frames support when one server tries to send an email to the other server the SMTP session will timeout when sending the email data e.g. you will see the following in the sending server’s delivery log (12 secs between the log entries below, simple text email which should take a few ms)
RSP: 354 Start mail input; end with <CRLF>.<CRLF>
Exception: Unable to write data to the transport connection: An existing connection was forcibly closed by the remote host.