[PATCH] Fix code extracting the MTA from Received: headers

[Dirk Hohndel]

On Thu, 08 Apr 2010 09:59:14 +0200, "Sebastian Spaeth" <Sebastian at SSpaeth.de> wrote:
> On 2010-04-07, Dirk Hohndel wrote:
> > 
> > The previous code made too many assumptions about the (sadly not
> > standardized) format of the Received headers. This version should
> > be more robust to deal with different variations.
> 
> This code might be useful for some, but I know it is not being useful
> for me. I use e.g. dreamhost.com as my mail provider and I never have my
> email domain name show up after the Received: by .....
> See my Received headers for your message below.

That's the funny thing about heuristics - they are always based on the
cases the author has access to. I run my own mail servers and they put
in useful Received lines. Dreamhost doesn't appear to do that - I'm sure
there are many other scenarios that I don't handle, yet.
Please keep them coming.
 
> On the other hand, it contains "for <sebastian at sspaeth.de>" stating the
> intended email address explicitely. IMHO, we should use this before we
> start some hand-wavy guessing.
> 
> Also, I have the "X-Original-To: sebastian at sspaeth.de" header. Is that
> something that we could make use of before starting to guess?

It's complicated. Some MTAs put in bogux "for <user at localhost>" or "for
UID 1000" into Received headers. I haven't seen any incorrect
"X-Original-To" headers, but wouldn't be surprised to see those be faked
or wrong, either.
Right now my plan is to do something like this:

1) look for my email address in To/Cc
2) look for my email in "for <email at add.res>" in Received headers
3) look for my email in X-Original-To
4) look for the domain of my email in Received headers (not just 1st)
5) punt and use default email address

Does that sound sane?

(and thanks for sending the headers - this really helps... can others
for whom the current code or the logic mentioned above wouldn't work
send their headers, too, please?)

/D

-- 
Dirk Hohndel
Intel Open Source Technology Center