Commit | Line | Data |
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2117e02e MW |
1 | The Hash Convention For Mail System Status Codes (HCMSSC) |
2 | D. J. Bernstein, djb@pobox.com | |
3 | 19970201 | |
4 | ||
5 | ||
6 | 1. Introduction | |
7 | ||
8 | RFC 1893 defines codes for mail delivery failures. For example, | |
9 | code 5.1.1 means that the specified mailbox does not exist. | |
10 | ||
11 | The qmail package sprays these codes all over the place, by adding a | |
12 | code to the text of every error message, preceded by a hash mark and | |
13 | surrounded by parentheses. It avoids using hash marks elsewhere. | |
14 | ||
15 | ||
16 | 2. Examples | |
17 | ||
18 | Here is a typical HCMSSC SMTP error message: | |
19 | ||
20 | 421 load average too high, please come back later (#4.3.2) | |
21 | ||
22 | Here is part of a typical HCMSSC bounce message: | |
23 | ||
24 | <mail-loop@silverton.berkeley.edu>: | |
25 | This is looping; it already has my Delivered-To line. (#5.7.1) | |
26 | ||
27 | But qmail doesn't use HCMSSC when it repeats another MTA's error | |
28 | message: | |
29 | ||
30 | <foo@heaven.af.mil>: | |
31 | 127.3.4.5 does not like recipient. | |
32 | Remote host said: 550 <foo>... User unknown (#5.1.1) | |
33 | ||
34 | ||
35 | 3. Security considerations | |
36 | ||
37 | Don't take drastic action upon seeing "(#"; it might not be HCMSSC. |