If you receive bounce messages from email addresses you have not sent email to, it is usually a result of spam or virus generated emails.
- Virus Generated emails: Some viruses can search the files of the infected computer for email addresses. The virus then sends itself as an attachment, using the email addresses it found on the infected computer as the ‘To’ and ‘From’ address fields in the email. Please ensure that you protect your computers and network with good anti-virus software.
- Spam generated emails: Spammers do not use their own email addresses to send spam. Instead, they search the internet for domain names and then fake the ‘From’ and ‘Reply-to’ fields in their spam email headers, by using addresses belonging to random domain names.
Faking email headers, by viruses or spammers, is called ‘Email Spoofing’ and is a common in the distribution of viruses and spam mail via the internet.
If your domain name was used in email spoofing, any failed deliveries will generate bounce messages back to your email addresses.
As there is nothing that prevents a virus or a spammer from using a false (spoofed) email address when sending mail, there is no way to prevent all bounce messages.
There are, however, some methods that can be used to help reduce the amount of bounce messages received, should your email account be spoofed by a spammer:
- Disable the catch-all mailbox
- Create a SPF record for your domain
- Note: The above are just some of the methods you can use to help reduce the amount of bounce back messages received. It is unfortunately not possible to prevent all bounce back messages due to the nature of emailing systems