# Spam Filters Spam filters are software programs that are designed to identify and block unwanted emails, also known as spam, from reaching a user's inbox. These filters use various techniques to identify spam emails, such as analyzing the content of the message, the sender's reputation, and the presence of certain keywords or phrases. One common technique used by spam filters is to compare the content of the email to a list of known spam keywords or phrases. If the email contains any of these keywords or phrases, it is more likely to be classified as spam. Spam filters may also use machine learning algorithms to analyze the content of emails and identify patterns that are common in spam emails. These patterns can include the use of certain words or phrases, the use of non-standard formatting, or the presence of links to suspicious websites. In addition to analyzing the content of emails, spam filters may also consider the reputation of the sender. For example, if the sender has a history of sending spam emails, the filter may be more likely to classify their emails as spam. Overall, the goal of a spam filter is to protect users from unwanted or potentially harmful emails by identifying and blocking spam before it reaches the user's inbox. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.smtpd.dev/master/faq/email-deliverability/spam-filters.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.