It is fairly common in Exchange Server 2010 environments for there to be applications or devices that send email to users. These are usually configured to relay email messages using an SMTP connection to a Hub Transport server. They almost never authenticate their SMTP session, so are considered anonymous senders by Exchange 2010.
In this scenario you may encounter an issue where the emails that end users receive show the SMTP address of the sender instead of the more friendly display name configured on the user mailbox that has that SMTP address.
For example an email from a scanner device will appear like this.
This will occur if the Receive Connector on the Hub Transport server is accepting anonymous email. Receive Connectors are not configured this way by default but many Exchange administrators enable it because it is the simplest way to allow applications or devices to send emails to internal recipients.
To enable Exchange Server 2010 to resolve the anonymous emails you need to configure the Authentication settings for the Receive Connector to enable the Externally Secured option.
However this is not possible for the Default Receive Connector due to the other Authentication settings that are already enabled.
Instead what you can do is create a relay connector for Exchange Server 2010 following the instructions here. Whether you restrict it to certain sender IP’s or allow your entire private network to use the relay connector is up to you.
Emails sent from devices using the new Receive Connector will resolve the name correctly from the GAL now.