Add "Received:" header to email msg in correct position?

[Burak Arslan]

On 05/06/14 12:47, Chris Angelico wrote:
> On Tue, May 6, 2014 at 7:15 PM, alister
> <alister.nospam.ware at ntlworld.com> wrote:
>> On Mon, 05 May 2014 19:51:15 +0000, Grant Edwards wrote:
>>
>>> I'm working on a Python app that receives an e-mail message via SMTP,
>>> does some trivial processing on it, and forwards it to another SMTP
>>> server.
>>>
>>> I'd like to do the polite thing and add a "Received:" header, but I
>>> can't figure out how to get Python's email module to add it in the
>>> correct place.  It always ends up at the "bottom" of the headers below
>>> From: To: etc.  It's supposed to go at the above all the Received:
>>> headers that where there when I received it.
>> Is this required or just being polite?
>> what I mean is does the standard state the headers must be in a
>> particular order or can they appear anywhere, you may be spending time
>> trying to resolve an issue that does not need fixing.
> Yes, it's required. RFC 2821 [1] section 3.8.2 says "prepend".
>
>

The rationale for "prepend" is to make it possible for MTAs to add their
"Received:" headers to messages without having to parse them.

So you're supposed to do the same: Just write your Received header,
followed by '\r\n', followed by the rest of the message to the socket
and you should be fine.

Best,
Burak