SEPPmail provides appropriate modules for the guided generation of the required connectors and rules via the "PowerShell Gallery" www.powershellgallery.com/packages/SEPPMail365/. Further information can be found in the chapter SEPPmail365 Powershell Module.

 

Furthermore, a correct ARC configuration is required, see ARC Sealing and subchapters. For multi-tenant capable SEPPmail Secure E-Mail Gateways, the chapter Exchange Online Configuration must also be observed.

 

Furthermore, the following configurations within Microsoft 365 should be observed:

 

Ignore the last sending IP address in the connector "[SEPPmail] Appliance -> ExchangeOnline"

This can be checked as follows:

 

GUI:

https://security.microsoft.com/skiplisting

Policies & rules > Threat policies > Enhanced Filtering for Connectors > Policies & rules > Enhanced Filtering for Connectors

Connector Name: [SEPPmail] Appliance -> ExchangeOnline

Setting: Automatically detect and skip the last IP address

 

Powershell:

Get-InboundConnector '[SEPPmai*' | fl EFSkipLastIP,EFSkipIPs
EFSkipLastIP : True
EFSkipIPs    : {}

 

 

"Connection filter policy" may not be active

This can be checked as follows:

 

GUI:

https://security.microsoft.com/antispam

Name: Connection filter Policy

Policies & rules > Threat policies > Anti-spam policies > Connection filter policy

 

Powershell:

# IPAllowList/AllowedSenders should not contain SEPPmail IPSs
Get-HostedContentFilterPolicy Default | fl AllowedSenders
AllowedSenders : {}

 

 

If the "Exchange Online" is implemented in this way, no additional configuration steps are required in the Mail Processing.

 

 

For further information, please also refer to https://www.seppmail.de/produkte/seppmail365/.