Re: Multiple "To:" and "Cc:" header lines in SMTP messages

[Ned Freed <[e-mail]>]

> This has been discussed on the DRUMS list, which is the list charged
> with clarifying matters  like these.

> The more-or-less conclusion was:

> - In certain situations (namely where the To: lines would be more than
>   8 Kbytes or so in length when unwrapped), certain mailers break,
>   whereas they accept multiple To: lines

Try 1K or 2K rather than 8K. Otherwise this is correct. It is also important to
note that the result when this happens is bounced mail, a far less desireable
outcome than failure to pick up some recipient addresses on a reply-to-all.

> - Therefore, people will go on breaking things onto multiple To: lines.

Agreed.

> - The practice should be frowned upon; having multiple To: lines with
>   a single address on each is silly. So it's a SHOULD NOT GENERATE.

I disagree; the proper recommendation is "SHOULD NOT generate a single field
for each separate address". The question of whether or not to generate multiple
field for lots of addresses should be left open, as it is too
environment-specific to recommend anything at this time.

> - The only recipient semantics that make sense is to treat it as if it
>   was a single long To: field. So it's a SHOULD ACCEPT.

I disagree; the proper recommendation is "MUST ACCEPT". And yes, this
absolutely is a change from RFC 822.

I run into problems with sendmail's limits at a different site a couple of
times every month on average so this is far from an academic point.

				Ned