SMTP Codes
Reply codes in numerical order Code Meaning 200 (nonstandard success response, see rfc876) 211 System status, or system help reply 214 Help message 220 <domain> Service ready 221 <domain> Service closing transmission channel 250 Requested mail action okay, completed 251 User not local; will forward to <forward-path> 354 Start mail input; end with <CRLF>.<CRLF> 421 <domain> Service not available, closing transmission channel 450 Requested mail action not taken: mailbox unavailable 451 Requested action aborted: local error in processing 452 Requested…