AS/400 SMTP supports 14 SMTP protocol commands (RFC 821). These program-generated
commands are used in the protocol between the SMTP client program and the SMTP
server program. The protocol command set identifies the various kinds of data
that the SMTP client and server can exchange.
| SMTP Command | What It Does | Supported |
|---|---|---|
| HELO (Hello) | Identify the SMTP sender to the SMTP receiver. | Yes |
| MAIL (Mail) | Start an e-mail transaction to deliver the e-mail to one or more recipients. | Yes |
| RCPT (Recipient) | Identify an individual recipient of e-mail. | Yes |
| DATA (Data) | Consider the lines following the command to be e-mail from the sender. | Yes |
| SEND (Send) | Deliver e-mail to one or more work stations. | |
| SOML (Send or mail) | Deliver e-mail to one or more work stations or recipients if the user is not active. | |
| SAML (Send and mail) | Deliver e-mail to one or more work stations and recipients if the user is not active. | |
| RSET (Reset) | End the current e-mail transaction. | Yes |
| VRFY (Verify) | Ask the receiver to confirm that a user has been identified. | Yes |
| EXPN (Expand) | Ask the receiver to confirm that a mailing list has been identified. | |
| HELP (Help) | Ask the receiver to send helpful information to the sender. | Yes |
| NOOP (Noop) | Ask the receiver to send a valid reply (but specify no other action). | Yes |
| QUIT (Quit) | Ask the receiver to send a valid reply, and then close the transmission channel. | Yes |
| TURN (Turn) | Ask the receiver to send a valid reply and then become the SMTP sender, or else ask the receiver to send a refusal reply and remain the SMTP receiver. |
Error codes
421 Service not available, closing transmission channel (This may be a
reply to any command if the service knows it must shut down)
450 Requested mail action not taken: mailbox unavailable (E.g., mailbox
busy)
451 Requested action aborted: local error in processing
452 Requested action not taken: insufficient system storage
500 Syntax error, command unrecognized (This may include errors such as
command line too long)
501 Syntax error in parameters or arguments
502 Command not implemented
503 Bad sequence of commands
504 Command parameter not implemented
550 Requested action not taken: mailbox unavailable (E.g., mailbox not
found, no access)
551 User not local; please try
552 Requested mail action aborted: exceeded storage allocation
553 Requested action not taken: mailbox name not allowed (E.g., mailbox
syntax incorrect)
554 Transaction failed
The other codes that provide you with helpful information about what's happening with your messages are:
211 System status, or system help reply
214 Help message (Information on how to use the receiver or the meaning
of a particular non-standard command; this reply is useful
only to the human user)
220 Service ready
221 Service closing transmission channel
250 Requested mail action okay, completed
251 User not local; will forward to
354 Start mail input; end with . (a dot)
8. Appendix - Collected Status Codes
X.1.0 Other address status
X.1.1 Bad destination mailbox address
X.1.2 Bad destination system address
X.1.3 Bad destination mailbox address syntax
X.1.4 Destination mailbox address ambiguous
X.1.5 Destination mailbox address valid
X.1.6 Mailbox has moved
X.1.7 Bad sender's mailbox address syntax
X.1.8 Bad sender's system address
X.2.0 Other or undefined mailbox status
X.2.1 Mailbox disabled, not accepting messages
X.2.2 Mailbox full
X.2.3 Message length exceeds administrative limit.
X.2.4 Mailing list expansion problem
X.3.0 Other or undefined mail system status
X.3.1 Mail system full
X.3.2 System not accepting network messages
X.3.3 System not capable of selected features
X.3.4 Message too big for system
X.4.0 Other or undefined network or routing status
X.4.1 No answer from host
X.4.2 Bad connection
X.4.3 Routing server failure
X.4.4 Unable to route
X.4.5 Network congestion
X.4.6 Routing loop detected
X.4.7 Delivery time expired
X.5.0 Other or undefined protocol status
X.5.1 Invalid command
X.5.2 Syntax error
X.5.3 Too many recipients
X.5.4 Invalid command arguments
X.5.5 Wrong protocol version
X.6.0 Other or undefined media error
X.6.1 Media not supported
X.6.2 Conversion required and prohibited
X.6.3 Conversion required but not supported
X.6.4 Conversion with loss performed
X.6.5 Conversion failed
X.7.0 Other or undefined security status
X.7.1 Delivery not authorized, message refused
X.7.2 Mailing list expansion prohibited
X.7.3 Security conversion required but not possible
X.7.4 Security features not supported
X.7.5 Cryptographic failure
X.7.6 Cryptographic algorithm not supported
X.7.7 Message integrity failure