B.1 Initial Reply

When a connection is established, the server sends an initial reply to the client. This reply has the following format:

220 hostname text <capabilities> msg-id

Its parts and their meaning are described in the following table:

hostname

The name of the host. It is determined automatically, unless set using hostname configuration file statement (see hostname directive).

text

Arbitrary text, as set via initial-banner-text configuration statement (see initial-banner-text).

capabilities

A comma-separated list of server capabilities. It is configured using capability statement (see Capabilities).

msg-id

A unique identifier similar to the format specified in RFC822, except that spaces and quoted pairs are not allowed within it.

This identifier will be used by the client when formulating the authentication string used in the AUTH command (see AUTH).

An example of initial reply follows:

220 Trurl.gnu.org.ua <auth.mime> <520.1212912026@Trurl.gnu.org.ua>