The Hash Convention For Mail System Status Codes (HCMSSC) INTERNET-DRAFT draft-bernstein-hcmssc-02.txt (expires 1 August 1997) This document is an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as ``work in progress.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Status of this memo This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Abstract RFC 1893 defines codes for mail delivery failures. For example, code 5.1.1 means that the specified mailbox does not exist. The qmail package sprays these codes all over the place, by adding a code to the text of every error message, preceded by a hash mark and surrounded by parentheses. It avoids using hash marks elsewhere. The Hash Convention For Mail System Status Codes (HCMSSC) D. J. Bernstein, djb@pobox.com 19970201 1. Introduction RFC 1893 defines codes for mail delivery failures. For example, code 5.1.1 means that the specified mailbox does not exist. The qmail package sprays these codes all over the place, by adding a code to the text of every error message, preceded by a hash mark and surrounded by parentheses. It avoids using hash marks elsewhere. 2. Examples Here is a typical HCMSSC SMTP error message: 421 load average too high, please come back later (#4.3.2) Here is part of a typical HCMSSC bounce message: : This is looping; it already has my Delivered-To line. (#5.7.1) But qmail doesn't use HCMSSC when it repeats another MTA's error message: : 127.3.4.5 does not like recipient. Remote host said: 550 ... User unknown (#5.1.1) 3. Security considerations Don't take drastic action upon seeing "(#"; it might not be HCMSSC.