From: "Chris Lewis" <clewis(_at_)nortelnetworks(_dot_)com>
...
Our rejection messages are pretty explicit: "this email was blocked by
...
Three problems:
1) A few MTAs manage not to show these messages to the sender AT ALL.
They just get a generic "it didn't work".
2) Many MTAs bury these strings so deep in bafflegab about NDRs/X.400
gunk and other sillyness (like listing each MX and retry in
excrutiatingly useless detail), that it's very easy to miss the message.
3) Language.
Here's an idea: extend RFC2821 to mandate a series of response codes
that MTAs can interpret and display to the senders.
Eg, some sort of SMTP policy return error:
55x <RFC2821 extended code> <policyflag> <how to get it fixed>
...
That does nothing at all for your first two problems. It also does
nothing for the third problem without a whole other system that does
not exist on all platforms and that in any case would require a lot
of new code in MTAs. That other system is required to translate the
extended codes into "localized" natural language. (Never mind that
the local language of the MTA doing the translating might be Spanish
while the language of the person using the MUA that finally sees the
bounce that might be delivered via a third MTA could be Finnish.)
However, the fact that fancy response codes wouldn't help your three
problems is not the worst. Worse is that it is yet another solution
that depends on deploying extended policyflag decoding software in
10,000,000 MTAs.
But wait, there's still more. In 35 years I've been in the software
trade, I've seen a lot of "error code" systems. *ALL* of them are
the same at the end. Sometimes the translation from a number (e.g.
"ABEND 1234" or "killed signal 10") to a string (e.g. "bad pointer")
is automatic and sometimes is manually finding the number in a list of
numbers and strings. In either case, you get a general message that
is meaningless except to the high priests of the system.
The best and only working solution is to do as SMTP does. That is to
include numbers that some software might but probably won't understand
as well as English for humans. The English can be tailored for special
cases such as including a telephone number. In special cases it can
be a language other than English.
Vernon Schryver vjs(_at_)rhyolite(_dot_)com
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