The message I received from "F. Scott Ophof" said: ... > > But if Internet mail contains addresses like <...-request@...> or > <owner-...@...> in the "Sender:" header to indicate the item comes > from an MLM, that to me doesn't ensure that those addresses will > consistently reflect the relevant mailing list. In other words, if > the "Sender:"-addr is: > <OWNER-listname@somewhere> or <listname-REQUEST@somewhere> > will the following ALWAYS be true? > <listname@somewhere> > or could it also be: > <[log in to unmask]> > or worse yet: > <[log in to unmask]> > > And besides <OWNER-..@..> and <..-REQUEST@..>, are there any other > such words that have the same ("guaranteed") behaviour? I see a number of people have responded to your question, and most seem to be on the mark. However (and you probably know this already) the use of prefixes "owner-" or suffix "-request" are really implementation-dependant. I know that the mail software I run (sendmail) looks for and "carbon-copies" to an "owner-" address when bouncing list-related mail. Our older machine which ran MMDF looked for a "-request" address instead. I would imagine that list maintainers would use a combination of "From:", "Reply-To:" and "Errors-To:" headers to ensure that postings to the list are replyable in a consistent manner. That way the burden of reliability rests with the maintainer rather than a list user. > > Recently I've seen items from some "Revised LISTSERV"s which have > "X-List:" headers, and that header-line has up to now consistently > displayed the relevant and correct list-address itself. > Do I sense an intention to use (and advertise using) that header for > that SINGLE purpose? If so, how does one ensure that that header > will only be used for THAT purpose? I've paraphrased a relevant portion of RFC 822 which explains the use of "X-" prefixed fields. . 4.7.4. EXTENSION-FIELD . . A limited number of common fields have been defined in . this document. As network mail requirements dictate, addi- . tional fields may be standardized. To provide user-defined . fields with a measure of safety, in name selection, such . extension-fields will never have names that begin with the . string "X-". . . Names of Extension-fields are registered with the Network . Information Center, SRI International, Menlo Park, California. . . . 4.7.5. USER-DEFINED-FIELD . . Individual users of network mail are free to define and . use additional header fields. Such fields must have names . which are not already used in the current specification or in . any definitions of extension-fields, and the overall syntax of . these user-defined-fields must conform to this specification's . rules for delimiting and folding fields. Due to the . extension-field publishing process, the name of a user- . defined-field may be pre-empted . . Note: The prefatory string "X-" will never be used in the . names of Extension-fields. This provides user-defined . fields with a protected set of names. I've seen various forms of "X-" addresses, none of which are really "standard" (like X-List and X-Mailing-List). They may be in (very) common use, but they don't appear to be guaranteed to exist in the future. > > Regards. > $$\ -Ravin __________________________________________________________________ Ravin Asar | National Science Foundation | 1800 G St. NW #440 | Washington, DC 20550 Official: [log in to unmask] | Phone: (202) 357-5934 Personal: [log in to unmask] | Fax: (202) 357-7663 __________________________________|_______________________________ IMHO