I found I had on open relay on a Exchange 2003 box and after changing the default SMTP virtual server properties by unchecking 'Anonymous access' I'm not receiving any inbound emails for external domains.
I've taken a look at the SMTPSVC1 logs and they are being rejected with a 454
Any ideas anyone?
If managing Active Directory using Windows Powershell® is making you feel like you stepped back in time, you are not alone. For nearly 20 years, AD admins around the world have used one tool for day-to-day AD management: Hyena. Discover why.