This appendix lists national, international, and industry standards related to electronic messaging and for which support is claimed by Sun Internet Mail Server 3.5. Most of these are Internet standards, published by the Internet Engineering Task Force (IETF) and approved by the Internet Activities Board (IAB). Standards documents from other sources are noted.

Several of the documents are listed with an obsolete status. These are included because they describe protocol features that were obsolete or replaced by later documents, but are still in widespread use.