https://app.knowbase.one/vault/rfc/docid/4195
RFC3834: Recommendations for Automatic Responses to Electronic Mail
Network Working Group K. Moore Request for Comments: 3834 University of Tennessee Category: Standards Track August 2004 Recommendations for Automatic Responses to Electronic Mail Status...
https://app.knowbase.one/vault/rfc/docid/5702
RFC5230: Sieve Email Filtering: Vacation Extension
Network Working Group T. Showalter Request for Comments: 5230 Category: Standards Track N. Freed, Ed. Sun Microsystems ...