SMTP reply codes
for the basic specification of SMTP; see also rfc1123 for
important additional information.
for information about enhanced status codes.
Check the RFC index for further mail-related RFCs.
This is a list of SMTP error
codes and log entries our favourite mail server will use to reply to e-mails
that had delivery problems. Note that this replies are only for e-mails that
are directed to our Xmail Server, not when Xmail is sending outside (in this
case you have the SLOG file and an e-mail response, if enabled in SERVER.TAB,
with similar errors from the other mail server, although each one has itís own
implementation of this codes).
As a general rule:
- if the first digit is 4 the Mail server has encountered a
temporary failure. If you are using a mail client (not web mail) you will get
an immediate response while sending.
Possible values are: 421, 451, 452
- if the first digit is 5 the Mail server has encountered a fatal error
and you will get back an e-mail from the postmaster (SERVER.TAB)
Possible values are: 500, 501, 503, 504, 505, 550, 551, 552, 557
- For SMTP Log file entries:
- 421 Service not available, closing transmission channel
- The Current Session Reached Smtp Timeout (Command Line: -St timeout)
- Xmail cannot create a new session (Reached Command Line: -SX nthreads)
- 451 Requested action aborted: local error in processing
- Xmail cannot create message file or set the related parameters/arguments. Possible causes: Network Error, Hardware Error, Disk Full...
- 452 Mailbox full
- Account over quota (Reached MaxMBSize in USER.TAB) or Insufficient disk space to receive the message. SMTP Log File: RCPT=EFULL
- 500 Syntax error, command unrecognised
- The sender issued a command that Xmail doesnít understand
- 501 Command not accepted
- Negative Response for VRFY command (AllowSmtpVRFY = 0 or not set in SERVER.TAB). SMTP Log File: VRFY=EACCESS
Negative Response for ETRN command (AllowSmtpETRN = 0 or not set in SERVER.TAB).SMTP Log File: ETRN=EACCESS
- 501 Syntax error in forward path
- The sender made a syntax error sending the RCPT TO:<xxx> command. SMTP Log File: RCPT=ESYNTAX
- 501 Syntax error in return path
- Negative Response for MAIL FROM:<> Command if Null Sender is not Allowed (AllowNullSender = 0 or not set in SERVER.TAB). SMTP Log File: SNDR=EEMPTY
The Return Path (MAIL FROM:<xxx>) is malformed or too long. SMTP Log File: SNDR=ESYNTAX
- 501 Syntax error in parameters or arguments
- The sender made a syntax error issuing one of the following commands: VRFY, ETRN, HELO, EHLO or AUTH
- 503 Bad sequence of commands
- The sender issued a bad sequence for one of the following commands: HELO, EHLO, MAIL FROM, RCPT TO, DATA or AUTH
- 503 Authentication failed
- Wrong User or Password. SMTP Log File: AUTH=EFAIL:TYPE Ö (PLAIN, LOGIN, CRAM-MD5, EXTRN)
- 504 Unknown authentication
- Xmail doesnít understand the authentication method specified by the sender
- 504 You are registered as spammer
- Sender IP address is listed in SPAM-ADDRESS.TAB file. SMTP Log File: SNDR=ESPAM
- 505 Your domain has not DNS/MX entries
- Negative Response if no SMTP server is found after issuing MAIL FROM:<xxx> command (when CheckMailerDomain = 1 is set in SERVER.TAB).
SMTP Log File: SNDR=ENODNS
- 550 Relay denied
- The Recipient Domain (RCPT TO:<xxx>) is not in Xmailís DOMAINS.TAB (or the sender IP address is not listed in SMTPRELAY.TAB). SMTP Log File: RCPT=ERELAY.
In rare casese you could get this error when you are behind a Cisco PIX firewall that blocks ESMTP Auth Commands (check this page).
- 550 Account disabled
- Negative Response if the Recipient account is disabled (ReceiveEnable = 0 in USER.TAB).
SMTP Log File: RCPT=EDSBL
- 550 Mailbox unavailable
- The Recipientís Domain part is Local but no User or Alias matches the Recipientís User part (USER.TAB or CMDALIASES Sub Directory).
SMTP Log File: RCPT=EAVAIL
- 550 String does not match anything
- Negative Response if VRFY is enabled (AllowSmtpVRFY = 1 in SERVER.TAB)
- 551 Server use forbidden
- Mail command is locked because Xmail requires authentication from any sender (mail-auth in SERVER.TAB)
- 551 Server access forbidden by your IP
- The Sender Domain is Listed in SMTP-RDNSCheck (SERVER.TAB). SMTP Log File: SNDRIP=ERDNS
The Sender Domain is Listed in CustMapsList Listed (SERVER.TAB).
SMTP Log File: SNDRIP=EIPMAP
- 552 Too many recipients
- Exceeded the maximum Recipients (RCPT TO:) available (Command Line: -Sr maxrcpts).
SMTP Log File: RCPT=ENBR
- 552 Message exceeds fixed maximum message size
- Exceeded the maximum message size (MaxMessageSize in USER.TAB or SERVER.TAB). SMTP Log File: SIZE=EBIG
- 557 Access denied
- The User cannot post to the mailing list (check MLUSER.TAB RW attributes).
SMTP Log File: RCPT=EACCESS