You can specify the criteria that email message addresses should have to be validated. Specifically, you can specify the characters that are permitted in addresses.
To specify address validation criteria
In the Control Center, click Protocols > SMTP > Settings.
On the SMTP tab, under Address Validation, select the criteria you want to implement as follows:
Allow email addresses to contain the percent character
Permits an email address to contain the percent sign.
This option is useful for legacy the systems that allow this symbol as a part of an email address.
Allow email addresses to start with a dash
Lets an address to have minus sign as the first character.
When you select this option, Symantec Messaging Gateway accepts email to any address that starts with the "-" character. When unchecked, Symantec Messaging Gateway rejects email to any recipient address starting with the "-" character.
Allow 8-bit characters in email addresses
Permits an email address that contains 8-bit characters.
Remove subaddress in recipient validation directory query
Provides support for subaddressing in recipient validation.
Subaddressing consists of additional text in the local portion of an email address (the part before the @), that follows a plus sign or a minus sign. When you select this option, Symantec Messaging Gateway removes the +detail or -detail portion of the email address before it completes an LDAP recipient validation query.
If you use plus or minus signs in email addresses for any purpose other than subaddressing, enabling this feature can cause recipient validation errors.