Smtp proxy outgoing delay
Fireware 12.8.2 U2 on FireboxV
I have a Office 365 connector allowing smtp relays from my site. For a long time, i have used a smtp filter, but now changed it to a smtp-proxy. It has Sender encryption required enabled and recipient encryption required enabled. Only TLSv1.2 is enabled.
AV is enabled plus ATP bloker (ATP with standard settings).
Sending out mails containing only text/html goes through the firebox within ms and routed to Office 365. Very fast as expected. As soon as a PDF is attached a mail the firebox takes forever to forward/release the mail to Microsoft´s gateway. Typical aroung 5-10 minuttes.
Here´s what Microsoft O365 log say:
_Message received by: AM7PR10MB3639.EURPRD10.PROD.OUTLOOK.COM using TLS1.2. There was a delay of 9 minutes prior to the message being received by Office 365.
Looking at FSM traffic monitor indicates the mail is forwarded instant and disable ATP and AV has no effect.
Why is Fireware so long to forward mails when PDF documents is attached, even with no scanning?