Description: URL for mailing list unsubscription Applicable protocol: Mail [18] Status: standards-track Author/change controller: IETF (mailto:iesg&ietf.org) Internet Engineering Task Force Specification document(s): RFC 2369 [13] Related information: Contains the URL to use to unsubscribe the mailing list from which this message was relayed. IANA Note: According to Web principles (per http://www.w3.org/TR/webarch/#safe- interaction), an HTTP GET request to the "List-Unsubscribe" URL should not change the subscription state without some further interaction involving something other than a "safe" HTTP interaction; e.g., a form response that performs an HTTP POST operation when a user confirms that they should be unsubscribed. In practice, many mailers do in fact complete the unsubscribe operation on receiving an HTTP GET to this URL, which can cause problems (e.g. when the URL is retrieved by a mail content scanner). The "List-Unsubscribe-Post" header provides a way to access the "List-Unsubscribe" URL with more predictable semantics.