Hi, We've been blocked from sending emails to a domain with a bounce -back (I've changed some of the info for security): You do not have permission to send to this recipient. For assistance, contact your system administrator. <OURSERVER.APCNET.local #5.7.1 smtp;550 5.7.1 NAME@aspreva.com>... HELO OURSEVERL.APCNET.local from RFC 2606 reserved domains blocked I've read we need to change our SMTP FQDN tothe external DNS record (mail.aspreva.com). What I haven't been able to find is any info on what sort of effect this will have on our system. I'm just scared of messing up our email. What's the risk involved with this change?

Just change the FQDN on the outbound connection properties of your virtual server facing the internet. In the past this could break functionality as the FQDN had to resolve internally, but MS loosened the requirement to provide for these kinds of Relay/Gateway setups. http://msexchangeteam.com/archive/2005/02/25/380481.aspx Cheers, Mark