Parser |
public bool AllowAddressesWithoutDomain { get; set; }
In general, you'll probably want this value to be true (the default) as it allows maximum interoperability with older email messages that may contain local UNIX addresses.
This option exists in order to allow parsing of mailbox addresses that do not have an @domain component. These types of addresses are rare and were typically only used when sending mail to other users on the same UNIX system.