Keith Moore wrote:
There also appears to be precedent for such transport limits
finding their way into the message format specification. RFC 822
had no line length limit; the 998 octet limit in 2822 sections
2.1.1, 2.3, and 3.5 appears to be derived from the SMTP transport
limitation.
yes, but that one is completely necessary. if you can't transport
a rfc 2822 message in SMTP then it isn't likely to go very far.
Practically speaking, true, though there *are* other transport
mechanisms (e.g. UUCP) for which it matters not. And I have
received messages via SMTP with longer lines than 998 octets.
not that it's a bad idea to bound the length of message-ids, but
using this as excuse to say that message-ids are bound by the SMTP
limit on address length is quite a stretch.
That was not my intent. I intended to point out that
1. there exists precedent for transport limits being introduced
into the message format, so in principle that should apply
to a msg-id length limit.
2. It would be more convenient, IMO, to have a uniform limit
for SMTP Path (a.k.a. angle-addr) and for msg-id rather than
two close but different limits. The comparison was by way of
pointing out the historical identity of the constructs (which
now differs w.r.t. CFWS), not as a justification. If there's
a reason why 250 works for NNTP and 256 doesn't, that's another
matter.