SUMMARY

By default, MailEnable does not allow plus-addressing, where a plus symbol is used to either denote a folder to send an email to, or a throw away part of an email address. MailEnable treats any email address with a plus symbol as part of a full address that has to be configured in MailEnable.

DETAIL

You can force MailEnable to accept an email addressed to a mailbox that has a plus address and is not mapped to a mailbox by enabling a Windows registry setting and restarting the MailEnable SMTP service. This has the effect of removing the plus component as the SMTP service accepts the email. So when an email is addressed to test+123@example.com, the SMTP service will try to send to test@example.com. This will affect all addresses, so if the plus symbol is used in existing email addresses they will no longer work unless the shortened version is also valid. Also, this will affect any emails being relayed through the server, as they will also have and plus-addressed email address altered.

For 64bit versions of Windows the registry key is:

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Mail Enable\Mail Enable\Connectors\SMTP]
"Plus Addressing"=dword:00000001

For 32bit versions of Windows the registry key is:

[HKEY_LOCAL_MACHINE\SOFTWARE\Mail Enable\Mail Enable\Connectors\SMTP]
"Plus Addressing"=dword:00000001