On Mon, 27 Mar 2006 13:51:38 EST, "Gartner, James" said: > > Does anyone know the max length of the Subject: line allowed through the > listserv (and any other mail systems)? > I've looked through the RFC 822, but I didn't see any max number > indicated. You can't find it in RFC822 because RFC822 was buggy and didn't actually say anything about the limit (although it *did* contain a description of using 'folding white space' to work around the limit, whatever it might be, in section 3.1.1. RFC2822 addressed the lack of clarity on this basic point: 2.1.1. Line Length Limits There are two limits that this standard places on the number of characters in a line. Each line of characters MUST be no more than 998 characters, and SHOULD be no more than 78 characters, excluding the CRLF. The 998 character limit is due to limitations in many implementations which send, receive, or store Internet Message Format messages that simply cannot handle more than 998 characters on a line. Receiving implementations would do well to handle an arbitrarily large number of characters in a line for robustness sake. However, there are so many implementations which (in compliance with the transport requirements of [RFC2821]) do not accept messages containing more than 1000 character including the CR and LF per line, it is important for implementations not to create such messages. The more conservative 78 character recommendation is to accommodate the many implementations of user interfaces that display these messages which may truncate, or disastrously wrap, the display of more than 78 characters per line, in spite of the fact that such implementations are non-conformant to the intent of this specification (and that of [RFC2821] if they actually cause information to be lost). Again, even though this limitation is put on messages, it is encumbant upon implementations which display messages to handle an arbitrarily large number of characters in a line (certainly at least up to the 998 character limit) for the sake of robustness. It then turns right around and section 2.2.3 specifically says that a header line can be "folded" to bypass the 998 limit: Each header field is logically a single line of characters comprising the field name, the colon, and the field body. For convenience however, and to deal with the 998/78 character limitations per line, the field body portion of a header field can be split into a multiple line representation; this is called "folding". The general rule is In other words, any implementation that doesn't allow for the fact that a header line can be over 998 octets(*) long after unfolding is buggy, pure and simple. (*) octets - originally used in documentation because a number of machines on the early internet were 36-bit boxes, where fitting 6 six-bit, 5 seven-bit, 4 9-bit bytes, or even 3 12-bit bytes (lots of bucky-bits there. ;) into a native word were common usages. Then the world standardized on 8-bit bytes and 36-bit boxes disappeared from memory of most. Now with things like UTF-8 on the loose, the distinction between octets and characters has once again become important....