1. Introduction

This is a reference manual for the EPP protocol as implemented by the FRED.

The global XSD schema all-2.4.0 has been taken as the baseline for the reference.

The manual describes protocol basics and the generic structure of messages in a nutshell (based on the main RFC standard), introduces registrable objects managed in the FRED, contains basic guidelines on the use of the namespaces and schemas and finally embraces an overview and a detailed reference of specific commands and responses, all interleaved with examples. Appendices contain overviews of result codes, error reasons and simple data types from schemas.

1.1. General workflow

This reference manual focuses on the syntax and allowed values but it does not describe how to use the registrar interface in general. The description of the command workflow can be found in this concept article: EPP client workflow. We recommend reading it to understand the broader context.

1.2. Conventions for describing XML structures

To describe XML structures, the following notation is used.

Element names are represented enclosed between the lower-than and the greater-than sign in a similar way as in actual XML documents, e.g. <nameSpace:elementName>. If a namespace prefix is collapsed into an asterisk, e.g. <*:elementName>, it means that the element is used (similarly) in several namespaces and these should be listed somewhere nearby.

After the element name, the number of allowed occurrences of the element is stated within parentheses and in bold, e.g. (1..3) means between one and three occurrences of an element, (0..1) means an optional element, (1) means an element must occur exactly once, (1..n) means that an element must occur at least once but the maximum number of occurrences is unbound, and so on.

Children of an element are formatted as a sub-list, hence indentation models the tree structure of XML. Although the lists are not numbered, elements must appear in the order they are listed. If a sub-list is introduced with the phrase one of, then the sub-list represents possible choices (only one of the listed elements may appear) instead of a sequence.

Attribute names are prefixed with an @, e.g. @attributeName. After the attribute name, the use of the attribute is specified if it is different from the default (attributes are optional), that is (R) if the attribute is required or (P) if the attribute is prohibited.

Element and attribute names are also generated to the index under the Symbols section. They are prefixed either with an Ⓔ for elements or with an ⓐ for attributes, so that they are distinguished from general index keys.