SMTP reply codes See rfc2821 for the basic specification of SMTP; see also rfc1123 for important additional information. See rfc1893 and rfc2034 for information about enhanced status codes. Check the RFC index for further mail-related RFCs. Reply codes in numerical order Code Meaning 200 (nonstandard success response, see rfc876) 211 System status, or system help reply 214 Help message 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 . 421 Service not available, closing transmission channel 450 Requested mail action not taken: mailbox unavailable 451 Requested action aborted: local error in processing 452 Requested action not taken: insufficient system storage 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 502 Command not implemented 503 Bad sequence of commands 504 Command parameter not implemented 521 does not accept mail (see rfc1846) 530 Access denied (???a Sendmailism) 550 Requested action not taken: mailbox unavailable 551 User not local; please try 552 Requested mail action aborted: exceeded storage allocation 553 Requested action not taken: mailbox name not allowed 554 Transaction failed Reply codes grouped by command Command Code Description connect 220 Service ready 421 Service not available, closing transmission channel HELO 250 Requested mail action okay, completed 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 504 Command parameter not implemented 521 does not accept mail [rfc1846] 421 Service not available, closing transmission channel EHLO 250 Requested mail action okay, completed 550 Not implemented 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 504 Command parameter not implemented 421 Service not available, closing transmission channel MAIL 250 Requested mail action okay, completed 552 Requested mail action aborted: exceeded storage allocation 451 Requested action aborted: local error in processing 452 Requested action not taken: insufficient system storage 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 421 Service not available, closing transmission channel RCPT 250 Requested mail action okay, completed 251 User not local; will forward to 550 Requested action not taken: mailbox unavailable 551 User not local; please try 552 Requested mail action aborted: exceeded storage allocation 553 Requested action not taken: mailbox name not allowed 450 Requested mail action not taken: mailbox unavailable 451 Requested action aborted: local error in processing 452 Requested action not taken: insufficient system storage 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 503 Bad sequence of commands 521 does not accept mail [rfc1846] 421 Service not available, closing transmission channel DATA 354 Start mail input; end with . 451 Requested action aborted: local error in processing 554 Transaction failed 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 503 Bad sequence of commands 421 Service not available, closing transmission channel received data 250 Requested mail action okay, completed 552 Requested mail action aborted: exceeded storage allocation 554 Transaction failed 451 Requested action aborted: local error in processing 452 Requested action not taken: insufficient system storage RSET 200 (nonstandard success response, see rfc876) 250 Requested mail action okay, completed 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 504 Command parameter not implemented 421 Service not available, closing transmission channel SEND 250 Requested mail action okay, completed 552 Requested mail action aborted: exceeded storage allocation 451 Requested action aborted: local error in processing 452 Requested action not taken: insufficient system storage 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 502 Command not implemented 421 Service not available, closing transmission channel SOML 250 Requested mail action okay, completed 552 Requested mail action aborted: exceeded storage allocation 451 Requested action aborted: local error in processing 452 Requested action not taken: insufficient system storage 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 502 Command not implemented 421 Service not available, closing transmission channel SAML 250 Requested mail action okay, completed 552 Requested mail action aborted: exceeded storage allocation 451 Requested action aborted: local error in processing 452 Requested action not taken: insufficient system storage 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 502 Command not implemented 421 Service not available, closing transmission channel VRFY 250 Requested mail action okay, completed 251 User not local; will forward to 550 Requested action not taken: mailbox unavailable 551 User not local; please try 553 Requested action not taken: mailbox name not allowed 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 502 Command not implemented 504 Command parameter not implemented 421 Service not available, closing transmission channel EXPN 250 Requested mail action okay, completed 550 Requested action not taken: mailbox unavailable 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 502 Command not implemented 504 Command parameter not implemented 421 Service not available, closing transmission channel HELP 211 System status, or system help reply 214 Help message 500 Syntax error, command unrecognised 501 Syntax error in parameters or arguments 502 Command not implemented 504 Command parameter not implemented 421 Service not available, closing transmission channel NOOP 200 (nonstandard success response, see rfc876) 250 Requested mail action okay, completed 500 Syntax error, command unrecognised 421 Service not available, closing transmission channel QUIT 221 Service closing transmission channel 500 Syntax error, command unrecognised TURN 250 Requested mail action okay, completed 502 Command not implemented 500 Syntax error, command unrecognised 503 Bad sequence of commands RJK | Contents