Noengang lurt på hva mailservere snakker om?
Her er en oversikt over såkalte SMTP-Relaycodes.
Kjekt å ha for folk som er i farta...

Kode         Beskrivelse
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 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          <domain> does not accept mail (see rfc1846)
530          Access denied (???a Sendmailism)
550          Requested action not taken: mailbox unavailable
551          User not local; please try <forward-path>
552          Requested mail action aborted: exceeded storage allocation
553          Requested action not taken: mailbox name not allowed
554          Transaction failed


Se forøvrig: RFC2821