qmail-smtpd returns responses beginning with 555 for syntax errors in the
parameters to MAIL and RCPT. From qmail-smtpd.c:
void err_syntax() { out("555 syntax error (#5.5.4)\r\n"); }
RFC 821 says that x5y status codes are for mail system problems, while x0y
status codes should be used for syntax errors:
The second digit encodes responses in specific categories:
x0z Syntax -- These replies refer to syntax errors,
syntactically correct commands that don't fit any
functional category, and unimplemented or superfluous
commands.
[...]
x5z Mail system -- These replies indicate the status of
the receiver mail system vis-a-vis the requested
transfer or other mail system action.
and it also specifically lists 501 as the error code to send for syntax
errors in parameters of a command:
501 Syntax error in parameters or arguments
draft-ietf-drums-smtpupd-10.txt seems to agree. Shouldn't qmail-smtpd use
501 as the status code in this case?
--
Russ Allbery ([EMAIL PROTECTED]) <URL:http://www.eyrie.org/~eagle/>
