On Sat, Sep 18, 2010 at 8:51 AM, Ned Freed
<ned(_dot_)freed(_at_)mrochek(_dot_)com> wrote:
Section 3.4. Address Specification of RFC2822 specifies
name-addr = [display-name] angle-addr
What are the length limits on the display-name field? I take it a long
display-name
value would simply be folded as described under 2.2.3. Long Header Fields
AFAICT the relevant specifications impose no limits on the size of the
display-name. What implementations actually do is another matter, of
course. I
believe I've encountered limits as low as 64 octets. I certainly wouldn't
recommend putting in stuff longer than 100 or so octets and expect it to
pass
through everything intact.
Thanks a lot for your replies, Ned and Hector!
Indeed, I tracked down the display-name rule in
display-name = phrase
phrase = 1*word / obs-phrase
where 1*word implies no length limit (RFC 2234)
When I asked about clients, I meant clients that connect to the mail
server to send an email message, not end-user
or display clients.
THat excludes the thnings that impose by far the shortest limits on these
fields.
For example, qmail-remote, and gateways when
passing a message to another server. Here
I thought the To: header being within the message they would not touch
it, or parse it and just pass it on, so
that "trace fields are prepended to the message" (A.4 in the Appendix )
Dream on. That's not how things work in th real world. Lots of intermediaries
perform all sorts of processing of header fields. The legality or illegality of
doing this is mostly irrelevant, since you have to deal with what's out there,
not what the standards-writers hoped would be out there, but even then,
specific header modifications are specifically condoned by vaiorus standards,
e.g., MIME downgrading.
In the specific case of To: fields, an obvious one is for submission servers to
rewrite addresses to eliminae short form names and other local crap.
Would such clients leave a display-name unchanged?
The answer is no, you cannot count on it.
I would think only
the total email length limit would come
into play, which is usually pretty large (measured in MB)
Again, you're dreaming if you think this is true.
Ned