Hey
I'm pretty sure what I need to do is possible I'm just not 100% sure the best way of going round it.
We are Hybrid / Office 365 - and we have a small number of Distribution lists which include internal and external recipients, these Distribution lists are also emailed by both internal and external people.
An internal person mailing the DL works fine, email goes to all recipients.
The problem is when an external person emails the DL - all the internal users receive the email as expected, but quite often the other external people on the DL never get the message - this is because when we relay the message we are effectively spoofing the external sender.
So what I think the best bet is to re-write the from address to an internal address for these specific emails but im not 100% sure how to do this in ironport.
So if user@external.com emails DL@internal.com the from address is rewritten to something@internal.com for the external users on the DL - this way the spf records will match and less likely to be caught in spam filters. But the rule needs to be only if that external person is emailing the DL - if they are emailing an internal recipient need the from address to remain the same.
I know its not ideal practice but need to get this working and cant think of any other way round.
Any suggestions appreciated!
