Flow mode or Proxy Mode on Email Inspection?

[Micky182]

Hello Guys,

i need an clarification about using proxy mode with deep inspection on emailfiltering.

I have and internal Exchange Server and today most of the traffic on port 25 use SSL.

So i want to switch from Flow Mode to proxy mode and inspect all traffic, but when i tried to do i wasn't to be able to recieve emails.

I think that FGT use only built-in SSL certificate to inspect traffic and Exchange cannot recognize this certificate. Need i to import this certificate in Exchange server or is possible to Inspect port 25 with our public cert like "mail.domain.com" ?

thank you very much for any hints!

[Markus]

Hi, Import your "mail.domain.com" cert into Fortigate and define the SSL profile. Thats the way it works. https://docs.fortinet.com/document/fortigate/6.2.0/cookbook/55107/protecting-an-ssl-server

Best

[Micky182]

Thank you very much Markus!

[Yurisk]

Additionally, if you want to apply AntiSpam profile to the inspected traffic to filter for spam, you have to use Proxy mode for the policy, not flow one.

[Markus]

Thanks Yuri It depends on the FOS Version. Antispam (FOS 7) seems also working in Flow Mode. Best,

Markus