Using an SPF Record to prevent email spoofing.

April 5, 2016 713 views
Email DNS Security Ubuntu

I successfully followed these instructions on How To Install and Configure Postfix as a Send-Only SMTP Server on Ubuntu 14.04 to configure Postfix on my server.

My Droplet's hostname is dummy.domain and this is the FQDN I used to configure Postfix. dummy.domain is of course not a real domain name, but using it I was able to send mail from user@dummy.domain to a Gmail account.

In the article How To use an SPF Record to Prevent Spoofing & Improve E-mail Reliability it mentions "Adding an SPF record to your DNS zone file is the best way to stop spammers from spoofing your domain. "

However, there is no DNS zone file for dummy.domain as it's not a real domain. So, is it possible to create an SPF record for this hostname and if so, where should I create it?

Many thanks in advance, Steve.

1 Answer

Without a zone file, there's no real way of creating one that I'm aware of, as SPF is just a type of DNS record.

Also, if the domain isn't real and/or doesn't functionally resolve anywhere, there's no way for other servers to perform queries on its DNS records. Even if the SPF record were to exist locally, there'd be no way for your email's recipient and/or other mail providers to get that information, thus rendering the local SPF record function-less.

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