UTF8 in from line???

[Claudio Junior]

Hey guys,

I have a curious case here which is a user sending emails using the google output server, which is being denied by my server. The error that is logged is:

Nov 16 18:36:48 srv04 postfix/cleanup[19091]: 5C1F31F8007D: discard: header From: =?UTF-8?Q?Andr=C3=A9_Luis_Vieira?= <andre....@kkk.kkk.kk> from mail -ua1-x92e.google.com[2607:f8b0:4864:20::92e]; from=<andre....@kkk.kkk.kk> to=<sergio....@xxxxxx.xxx.xx> proto=ESMTP helo=<mail-ua1-x92e.google.com>

The email is not arriving at the destination, and an "error" is not being returned to the origin of the email. I did a test on the swan and got the following negotiation:

csjunior@server01:~$ swaks --to csju...@xxxxxxxx.xxx.xx --from andre....@kkk.kkk.kk --server mail.xxxxxxxx.xxx.xx --header 'From: =?UTF-8 ?Q?Andr=C3=A9_Luis_Vieira?= <andre....@kkk.kkk.kk>'
=== Trying mail.xxxxxxxx.xxx.xx:25...
=== Connected to mail.xxxxxxxx.xxx.xx.
<- 220 srv04.xxxxxxxx.xxx.xx ESMTP
-> EHLO server01.yyyyyyyyy.yyy
<- 250-srv04.xxxxxxxx.xxx.xx
<- 250-PIPELINING
<- 250-SIZE
<- 250-VRFY
<- 250-ETRN
<- 250-STARTTLS
<- 250-AUTH PLAIN LOGIN
<- 250-AUTH=PLAIN LOGIN
<- 250-ENHANCEDSTATUSCODES
<- 250-8BITMIME
<- 250 DSN
-> MAIL FROM:<andre....@kkk.kkk.kk>
<- 250 2.1.0 Ok
-> RCPT TO:<csju...@xxxxxxxx.xxx.xx>
<- 250 2.1.5 Ok
-> DATE
<-354 End data with <CR><LF>.<CR><LF>
-> Date: Wed, 17 Nov 2021 10:18:49 -0300
-> To: csju...@xxxxxxxx.xxx.xx
-> From: =?UTF-8?Q?Andr=C3=A9_Luis_Vieira?= <andre....@kkk.kkk.kk>
-> Subject: test Wed, 17 Nov 2021 10:18:49 -0300
-> Message-Id: <2021111710...@server01.yyyyyyyy.yyy>
-> X-Mailer: swaks v20181104.0 jetmore.org/john/code/swaks/
->
-> This is a test mailing
->
->
-> .
<- 250 2.0.0 Ok: queued as 7F4E31F8007D
-> QUIT
<- 221 2.0.0 Bye
=== Connection closed with remote host.
csjunior@server01:~$


What can be done to resolve this? Is it a source or destination error?

Note: in order to protect the users, I put a mask over the domain names. Fighting against spam sucks!

Thanks

Claudio Jr.

[Bob Nichols]

On 2021-11-18 Thu 18:25:08 -0800, Claudio Junior wrote:
> I have a curious case here which is a user sending emails using the
> google output server, which is being denied by my server. The error
> that is logged is:
>
> Nov 16 18:36:48 srv04 postfix/cleanup[19091]: 5C1F31F8007D: discard: header From: =?UTF-8?Q?Andr=C3=A9_Luis_Vieira?= <andre....@kkk.kkk.kk> from mail -ua1-x92e.google.com[2607:f8b0:4864:20::92e]; from=<andre....@kkk.kkk.kk> to=<sergio....@xxxxxx.xxx.xx> proto=ESMTP helo=<mail-ua1-x92e.google.com>
>
> The email is not arriving at the destination, and an "error" is not
> being returned to the origin of the email.
>

> What can be done to resolve this?

The log message above suggests that the header_checks access file
contains a DISCARD entry which matches that "From" header.