Reply-To header

[Steve Holden]

Steven D'Aprano wrote:
> Mike Meyer wrote:
> 
> 
>>When I notice that a list is broken (RFC 2822 says that
>>reply-to is for the *author* of the message; anyone else setting it is
>>doing so in violation of the RFC, and hence broken, no matter how
>>useful it may be), 
> 
> 
> Since when did obeying the RFC become important in and 
> of itself? If there was a RFC that said that passwords 
> should be limited to one alphanumeric character, would 
> we slavishly follow it?
> 
The day such an RFC is published will be the day RFCs stop being useful. 
Until that time the RFCs are pretty much the guide to desired behaviour 
on the Internet, and anyone willfully disobeying them is asking for trouble.

If an RFC was published saying you should give yourself a kick in the 
head for such inanity would you do it? ;-)

> I have been known to change the reply-to address from 
> the address I am sending from (me at work for example) to 
> the address I want the reply to go to (me at home). There 
> are many times I'm emailing people I know can't cope 
> with the complicated task of changing the To address of 
> their reply, so I change the reply-to header so that 
> their reply goes where I want it to go to (which might 
> be another email address of mine, or a different 
> person, or a mailing list).
> 
This is an entirely sensible use of the Reply-To address, and indeed 
many mail clients nowadays will allow you to set a Reply-To for each of 
the accounts you create.

Having in the past used accounts where the Reply-To was different from 
the originating address I am only too well aware, though, that there are 
several email clients and mailing systems that *don't* correctly action 
Reply-To, and instead respond to the originating address directly.

> That's what reply to means, surely? What is the point 
> of a reply-to header that must be the sender, since you 
> already have a header that gives you the sender.
> 
Quite.

> If the RFC says that the reply-to header doesn't 
> actually mean the address the reply should go to, but 
> only the sender, then the RFC is broken. "Where the 
> reply goes to" is a *human* decision, not a technical 
> one. If I send you an email saying "Please reply to 
> president at whitehouse.gov" then your mailer should 
> honour that (although, since we are all adults, you 
> should have the freedom to ignore my request and make a 
> nuisance of yourself by emailing your reply to a 
> different address).
> 
Of course, few users actually bother to even check whether the address 
their mailer generates corresponds to anything in the original message, 
instead blindly relying on their software's behaviour for correctness 
(see above).

> Likewise, if I set the reply address to the list, then 
> your mailer should reply to the list. Perhaps you can 
> argue that *my decision* to have replies go to the list 
> is a bad one, but that's a social issue, not a 
> technical one.
> 
Most mailers will indeed do this. Except the ones that don't (see above 
...).

> 
> 
>>I tell my mailer to ignore reply-to on mail from
>>that list. Similarly, I no longer try and explain to people how long
>>lines violate RFCs and are a pain to read in well-behave mail readers,
> 
[...]

Having a mailer that can vary its behaviour from one list to another is 
something that's way beyond 90% of Internet mail users nowadays. Sadly 
we are talking about a problem that the majority of users don't even 
understand, happily sending their rich-text and HTML emails to mailing 
lists/newsgroups as well as individuals.

regards
  Steve
-- 
Steve Holden       +44 150 684 7255  +1 800 494 3119
Holden Web LLC                     www.holdenweb.com
PyCon TX 2006                  www.python.org/pycon/