From user-a@srv-a
Authentication-Results: srv-a
;spf=none (no DNS record found)
;dkim=pass header.b=*
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
d=srv-b; s=sel77; *
h=from:subject:to:from:subject:date:to:cc:message-id;
bh=*
b=*
*
*
*
*
*
*
*
From: user-b@srv-b
To: user-a@srv-a
Subject: Feliz primavera!
Espero que florezcas feliz!