dee @ cybercash.com ("Donald E. Eastlake") writes:
This is really an RFC 821 question, but can anyone tell me what
typical SMTP clients do if they get a 3xx reply after a MAIL or RCPT
command?
RFC 821 says this is an "error" as opposed to a "failure" but do they
(1) abort the whole conversation, (2) give up on that piece of mail,
or (3) (for RCPT) just treat it like a failure and go on to the next
recipient, or (4) something else I haven't though of?
I'd appreaciate any info on this.
Donald
The following excerpt from rfc1123 briefly mentions "interoperability problems
have arisen" but I didn't see anything that describes a required "action" for
this occurrence. I also didn't see where (in rfc821) a 3xx reply was
categorized as an "error" as opposed to a "failure" but only general guidelines
that receivers must adhere to the listed reply codes. This is an interesting
question that I am also looking for additional clarification.
5.2.10 SMTP Replies: RFC-821 Section 4.2
A receiver-SMTP SHOULD send only the reply codes listed in
section 4.2.2 of RFC-821 or in this document. A receiver-SMTP
SHOULD use the text shown in examples in RFC-821 whenever
appropriate.
A sender-SMTP MUST determine its actions only by the reply
code, not by the text (except for 251 and 551 replies); any
text, including no text at all, must be acceptable. The space
(blank) following the reply code is considered part of the
text. Whenever possible, a sender-SMTP SHOULD test only the
first digit of the reply code, as specified in Appendix E of
RFC-821.
DISCUSSION:
Interoperability problems have arisen with SMTP systems
using reply codes that are not listed explicitly in RFC-
821 Section 4.3 but are legal according to the theory of
reply codes explained in Appendix E.