The same goes for spammers or phishers using your email list domain to send fraudulent emails. Domain monitoring tools are a good start, but there are other ways to protect yourself before a breach occurs. First, you can "Sign the back of your credit card". What do we mean by that? You can enable dkim authentication. Dkim (domain keys identified mail) is basically a signature that any sender can apply to their email messages. This signature makes it clear that the supposed sender of the message is, in fact, the sender of the message.
For example, a company called "Dog bandanas" will sign their messages with the domain dogbandanas Com to confirm that the message was indeed sent by "Dog bandanas". You can learn more about setting up dkim here. Unfortunately, sometimes cashiers do not verify the signature on the back of the card. A deeper layer of security would be to have the cashier email list verify the identity of the person presenting the credit card for the purchase. This would be like enabling a dmarc policy for your domain. Dmarc (domain-based message authentication, reporting & conformance) is a standard that builds on dkim. It allows the domain owner to create a policy that tells mailbox providers what to do if email fails spf and dkim checks.
Think of it as additional security questions when email list logging in to check your credit report. It's important to consider these additional security measures if your domain is in an industry more susceptible to phishing attacks. What about subdomains? Bdkdadw41 clothesline if you want to create subdomains to send specific areas of communication from your domain, make sure you're doing it for the right reasons. Taking additional “lines of credit” — or, in this case, creating new subdomains — isn’t like starting over with a new domain. You can't escape previous bad sending behavior that happened with your parent domain. Some mailbox providers may treat subdomains as separate entities, but more sophisticated mailbox providers like gmail will average the domain reputation of your parent domain