Re: Fwd: Mail delivery failed: returning message to sender

[Niels Thykier <niels@thykier.net>]

Andreas Metzler:
> [...]
> 
> Hello,
> 
> No, the encoding was not correct. Compare how you (your MUA) just did it in
> this message with the rejected one.
> 
>   From: =?UTF-8?Q?TOMAS_MARTI=c5=a0IUS?= <tomas@puga.vdu.lt>
> 
>   From: =?utf-8?b?VG9tYXMgTWFydGnFoWl1cyA8dG9tYXNAcHVnYS52ZHUubHQ+?=
> 


Hi,

The latter is "simply" a base64 encoding:

$ echo 'VG9tYXMgTWFydGnFoWl1cyA8dG9tYXNAcHVnYS52ZHUubHQ+' | base64 -d
Tomas Martišius <tomas@puga.vdu.lt>

Note the difference between "=?UTF-8?Q?" vs. "=?UTF-8?b?" (Q vs. b).  I
presume the "b" is for "binary" or/and "Base64 encoded" vs. Q which
would be "quoted printed" or something like that.

I am not an expert on permitted ways of quoting UTF-8 in mail headers,
but the base64 method does not seem entirely inconceivable for some RFC
to support that (especially not considering you can encode the body with
base64).

Thanks,
~Niels