I'm working on switching from internal on-premises anti-spam appliance to cloud ESS and wondering what inbound/outbound firewall rules should look like.
Presently we have a NAT rule NAT-ing our outside SMTP email IP address to the internal Barracuda IP, I imagine this could go away.
We also have rules allowing in-bound SMTP traffic (WAN > LAN) for our outside smtp email IP address, also a rule allowing out-bound traffic allowing our internal email server IP address to send SMTP email.
This is all within a SonicWall firewall.
I think we need the various Barracuda-specific IP ranges allowed in/out bound traffic to our internal on-premises Exchange 2016 IP address, correct??
And disable anything to do with the on-premises physical Barracuda appliance??
Thank you, Tom