Spoof means to cheat or trick. When it comes to emails, spoofing is a technique used to trick recipients into opening an email coming from a fraudulent source. Thus, email spoofing is creating a bogus email address or faking the email address of another user.
Most email service providers including Pepipost have security features that prevent unauthorized users from sending messages. Additionally, you can create DKIM and SPF records in your DNS to authenticate the sender domain. This reduces attempts of spoofing using your domain name.
However, spoofers often send spam messages from their own SMTP, which allows them to use fake email addresses. Email spoofing via SMTP is possible because it does not provide a mechanism for address authentication. Although email address authentication protocols such as SPF and DKIM have been specified to fight email spoofing, adoption of those mechanisms by most businesses has been slow. Therefore, it is possible to receive email from an address that is not the actual address of the person sending the message. Spoofing can be used in conjunction with phishing emails to spread viruses or other malicious programs.
Pepipost has a strict policy for offenders. If we find that our customers are sending spoofed or phishing emails, we will ban the account completely. We maintain a highly reputable good sender community by eliminating spoofers and spammers.
You can always file a spoofing or phishing report with the Federal Trade Commission
Also, do you think you have a good email sending reputation? Find out and improve.
Also, check if emails from your domain are landing in Spam - Email Blacklist Checker Tool