SECURING EMAIL COMMUNICATIONS

Methods and systems are provided for securing email communications. According to one embodiment, a network device evaluates whether a domain name of a target recipient of an outbound email is present in a local white list or a local black list. If it is found in the local white list, the email is transmitted to the target recipient. If it is found in the local black list, transmission of the email to the target recipient is prevented. When the domain name is not present in the local black list and the local whitelist, a global doppelganger database is checked. If it is found in the global doppelganger database, the email is handled according to a corresponding acceptability flag; otherwise, the validity of the domain name is dynamically verified and handled according to the verification result.