SMTP Reply codes rfc5348

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SMTP reply codes

SMTP Reply codes are used to determine the error in the message, SMTP(Simple Mail Transfer Protocol) is a standard protocol for sending emails, the client sends and the server responds, a response is with the 3 digit code which contains the meaning for the response with the codes, find the below SMTP reply codes

SMTP Reply codes

CodeDescription
211System status, or system help reply.
214Help message.
220Domain service ready.Ready to start TLS.
221Domain service closing transmission channel.
250OK, queuing for node node started. Requested mail action okay, completed.
251OK, no messages waiting for node node. User not local, will forward to forwardpath.
252OK, pending messages for node node started. Cannot VRFY user (e.g., info is not local), but will take message for this user and attempt delivery.
253OK, messages pending messages for node node started.
354Start mail input; end with ..
355Octet-offset is the transaction offset.
421Domain service not available, closing transmission channel.
432A password transition is needed.
450Requested mail action not taken: mailbox unavailable. ATRN request refused.
451Requested action aborted: local error in processing. Unable to process ATRN request now
452Requested action not taken: insufficient system storage.
453You have no mail.
454TLS not available due to temporary reason. Encryption required for requested authentication mechanism.
458Unable to queue messages for node node.
459Node node not allowed: reason.
500Command not recognized: command. Syntax error.
501Syntax error, no parameters allowed.
502Command not implemented.
503Bad sequence of commands.
504Command parameter not implemented.
521Machine does not accept mail.
530Must issue a STARTTLS command first. Encryption required for requested authentication mechanism.
534Authentication mechanism is too weak.
538Encryption required for requested authentication mechanism.
550Requested action not taken: mailbox unavailable.
551User not local; please try forwardpath.
552Requested mail action aborted: exceeded storage allocation.
553Requested action not taken: mailbox name not allowed.
554Transaction failed.

See Also

Simple Mail Transfer Protocol (SMTP) Enhanced Status Codes Registry – https://www.iana.org/assignments/smtp-enhanced-status-codes/smtp-enhanced-status-codes.xhtml

IP subnet calculator – https://computercarriage.com/2021/06/03/simple-ip-calculator-subnet-using-korn-shell-script-v1-0/

Shell script basics – https://computercarriage.com/2020/12/06/shell-script-basics/

rfc5248 – https://datatracker.ietf.org/doc/html/rfc5248

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