Attachments fail to deliver after enabling TLS on incoming listners

[skc455]

Hi, I had a weird issue today, wanted to see if anyone else had experienced the same, if so how did you resolve it?

We have two ironport appliances running in cluster mode. I have enabled TLS preferred verify under mail flow policies << InboundMail policy. Since I have enabled none of our internal employees were receiving emails with attachments. Emails without attachments are delivered okay. Only those which have attachments are not being delivered. We are using default ironport cert for now. 

[Libin Varghese]

The only reason I can currently think of would be a firewall/proxy inspecting SSL packets and silently dropping them or interrupting it some other way.

You may want to ensure there is no SSL inspection being done in the network.

Apart from that it would require packet captures to be setup on the ESA to see what's going on during the SSL handshake and later when an attachment is sent.

Regards,

Libin