Continuing the discussion from Replacing Mailing lists: Email-In:
Sorry if this is already discussed. It’s rather hard to search for the 2-character “CC” on Discourse. 
Is there (ever or still) a valid reason to reject emails where the Discourse email address is on the CC or BCC line? If so, what’s the rationale? We have had this happen a few times recently with confused users.
I was asked about this on Monday. A user wanted to send an email to a consultant with a cc to our staff mailing list on discourse. The idea she had (I think) was to enable staff to reply to both consultant and staff for follow up.
This doesn’t have predictable results and so I encouraged her to write two separate emails. One to staff and another to the consultant. Otherwise if the consultant replies all it will generate an error from discourse, and the replies from the staff won’t get to the consultant.
Discourse and email are like oil and water, sadly. But folks are getting used to it and we’re getting good results.
Our scenario is quite similar. The questions come from addresses (aliases) associated with specific categories that are handled like team distribution lists, like yours.
Seems to really confuse users. How best to improve the experience? At a minimum, I think the error message here could be improved.
OK, what does it currently say and what do you think it should say?
Discourse fires off the “I didn’t recognize that To: address” error reply if it’s in the CC:.
Here’s an important question: What part of the email should be posted?
It will be difficult to strip out the email addresses from the “Forwarded Message” block, as (of course!) every email client will do it differently.
If it is not wanted to let in emails send to a category through Cc: or Bcc: I at least want to suppress the reject email. What do you think?
Reason is I currently try to move people away from using email and get them used to Discourse. So I let Discourse harvest emails send to some mailinglists. As soon as there is such an mailinglist address added to the Cc: field instead of To: the sender gets confronted with the reject email send by Discourse. This is confusing people.
Has there been any change in this behavior with 1.5, @zogstrip?
When an email is received, we look for email addresses in all the destinations fields (To, Cc and Bcc). If at least one matches a reply address, a group or a category incoming email address, then the mail will be processed.
Talvez eu esteja perdendo algo, mas não existe um cabeçalho Bcc?
Vejo que o código-fonte do Discourse verifica isso, mas a ideia por trás do Bcc não é que esses endereços de e-mail nunca devem aparecer em um cabeçalho?
BCC é uma opção de cabeçalho válida; se o endereço do destinatário não estivesse no cabeçalho, a mensagem não chegaria a ele.
Uma vez que um e-mail com múltiplos destinatários atinge o MTA, ele é enviado por destinatário. Usuários no campo para/CC verão um cabeçalho sem BCC, e qualquer usuário com cópia oculta verá seu endereço especificado como BCC:
O roteamento é feito por envelope RFC821; os cabeçalhos da mensagem não são utilizados para isso.
Fiz mais algumas pesquisas e há, de fato, um cabeçalho Bcc na especificação, mas nunca vi sendo usado.
Na prática, MTAs e/ou clientes de e-mail parecem omitir o cabeçalho Bcc nas mensagens, mesmo quando são entregues a um dos destinatários em Bcc.
Essa é também a minha experiência. Não me lembro de nunca ter visto meu endereço de e-mail em um e-mail que foi enviado para mim em cópia oculta.
@zogstrip você saberia o que pode estar acontecendo?
Parece que antes havia uma verificação no envelope neste commit: add support for incoming emails in CC/BCC fields · discourse/discourse@93d1cc6 · GitHub (especificamente discourse/lib/email/receiver.rb at 93d1cc6294085008e025bb3032b231a6a81c6480 · discourse/discourse · GitHub), mas parece que ela foi refactorada em versões mais recentes do receiver.rb.
Há alguma chance de as mudanças destacadas por @k4rtik voltarem? Enfrentei esse problema recentemente. Nossos usuários gostariam de enviar atualizações por meio de BCC.