I have recently migrated from Exchange 2013. I have several internal IP addresses that I would like to allow to send email from via applications and also a scanner. I have set up a receive connector and allowed the internal IP range and anonymous access and have verified that it works fine.
It seems the anti-spam system seems to to block the email as I get a notification on the administrators account of failed delivery. I could allow the spam system to bypass the domain but this would allow any spam with the domain name to come through.
Any ideas?