Initial situation:

Microsoft Outlook/Exchange is used as an email system. The proprietary Microsoft function "Send on behalf of" is to be used.

 

Question:

Which key will be used with an email sent via the MS Exchange delegation rule?

 

Answer:

For sending emails by means of "Send on behalf of", the headers are set according to the table below.

Here, Max Mustermann is sending an email as a delegate of the collective mailbox Support (delegator), i.e. "max.mustermann@company.tld on behalf of support@firma.tld".

 

 

The SEPPmail Secure E-Mail Gateway uses the sender from the FROM header for selecting the signature certificate. Signing is therefore done with the key of the delegate.

The signature is therefore recognised as valid by all common email clients, provided that the email was not changed on the transmission route.