NDR Attachements?

Occasional Contributor

Hey guys,


We're using Exchange Online and have a custom extension filter. Our Problem now is, that NDR's sent by the postmaster are being quarantined. If we deactivate the extension filter, the NDR's get through without any problem. Does an NDR contain any attachments? If yes, which File-Extension does it contain?


Thanks in advance. :)

2 Replies

Hey @cedric_menzi 


It should be .eml , you can login into OWA to see the actual attachment, earlier outlook used to allow you to click on the paperclip symbol to see the actual attachment but i guess one cant click through it now.

Hey @harveer singh

I can see the .eml-File in the OWA, but It it isn't blocked anywhere...

(By the way, I use Exchange Online.)