Email Spoofing

Email spoofing is email activity in which the sender address and other parts of the email header are altered to appear as though the email originated from a different source. Because core SMTP doesn't provide any authentication, it is easy to impersonate and forge emails.

Although there may be legitimate reasons to spoof an address, these techniques are commonly used in spam and phishing emails to hide the origin of the email message.

A number of measures to address spoofing have been proposed, including: SPF, Sender ID, and DKIM, and these are now widely implemented.