Spoofing is the act of sending email messages with a forged sender address, in an attempt to disguise the true origin of the message. This can be done for malicious purposes, such as attempting to steal sensitive information or spreading malware. One way to protect against spoofing is email domain warming, where email senders gradually increase the volume and variety of their email communications from a new domain.

There are several types of email spoofing, but the most common is sender address spoofing. This type of spoofing occurs when the email sender's address is manipulated to make it appear as though the email is coming from a different source. This can be done by changing the email address in the "from" field, or by using a fake email address altogether.

Other types of email spoofing include email content spoofing and email header spoofing. Email content spoofing occurs when the email's content is manipulated to make it appear as though it is coming from a different source. This can be done by changing the email's subject line, or by adding fake information to the email body. email header spoofing occurs when the email headers are manipulated to make it appear as though the email is coming from a different source. This can be done by changing the "from" field, or by adding fake information to the email headers.