37 lines
1 KiB
Text
37 lines
1 KiB
Text
The Hash Convention For Mail System Status Codes (HCMSSC)
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D. J. Bernstein, djb@pobox.com
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19970201
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1. Introduction
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RFC 1893 defines codes for mail delivery failures. For example,
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code 5.1.1 means that the specified mailbox does not exist.
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The qmail package sprays these codes all over the place, by adding a
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code to the text of every error message, preceded by a hash mark and
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surrounded by parentheses. It avoids using hash marks elsewhere.
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2. Examples
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Here is a typical HCMSSC SMTP error message:
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421 load average too high, please come back later (#4.3.2)
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Here is part of a typical HCMSSC bounce message:
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<mail-loop@silverton.berkeley.edu>:
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This is looping; it already has my Delivered-To line. (#5.7.1)
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But qmail doesn't use HCMSSC when it repeats another MTA's error
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message:
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<foo@heaven.af.mil>:
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127.3.4.5 does not like recipient.
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Remote host said: 550 <foo>... User unknown (#5.1.1)
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3. Security considerations
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Don't take drastic action upon seeing "(#"; it might not be HCMSSC.
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