How To Check SMTP Logs in Windows Server (IIS)?

Open Start > Programs > Administrative Tools > Internet Information Service (IIS) Manager. Right click "Default SMTP Virtual Server" and choose "Properties". Check "Enable logging".

You can check the SMTP log files at C:\WINDOWS\system32\LogFiles\SMTPSVC1.

SMTP status codes

Status Code Description
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 unrecognized
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
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

How To Check SMTP Logs in Windows Server (IIS)?