I have a public mail server (Linux + postfix) and some clients using it. The server is properly configured, included DKIM and SPF validation. But emails from only a few of my clients are being marked as SPAM, because the client-ip doesn't match with allowed senders' IPs and the SPF validation fails:
Received-SPF: fail (google.com: domain of email@example.com does not designate 22.214.171.124 as permitted sender) client-ip=126.96.36.199;
Of course, 188.8.131.52 is not the IP of my server.
I don't know the reason, because they are sending mails from properly (AFAIK) configured Outlooks. Even though, the DKIM validation pass, so, the email pass through my server before is sent.
Has anybody experienced similar issues and could tell me any possible reasons for that mismatch?
Here are the headers (mailboxes have been replaced by xxxxx):
Delivered-To: firstname.lastname@example.org Received: by 10.194.70.103 with SMTP id l7csp1376984wju; Fri, 2 Sep 2016 04:49:17 -0700 (PDT) X-Received: by 10.28.154.208 with SMTP id c199mr2895670wme.102.1472816956397; Fri, 02 Sep 2016 04:49:16 -0700 (PDT) Authentication-Results: mx.google.com; spf=fail (google.com: domain of email@example.com does not designate 184.108.40.206 as permitted sender) firstname.lastname@example.org; dkim=pass email@example.com Received-SPF: fail (google.com: domain of firstname.lastname@example.org does not designate 220.127.116.11 as permitted sender) client-ip=18.104.22.168; Received: by 10.28.127.2 with POP3 id a2mf7718962wmd.1; Fri, 02 Sep 2016 04:49:16 -0700 (PDT) X-Gmail-Fetch-Info: email@example.com 1 ns.cydsur.com 995 firstname.lastname@example.org Return-Path: <email@example.com> Delivered-To: firstname.lastname@example.org Received: from DANIEL (20.red-217-125-48.staticip.rima-tde.net [22.214.171.124]) (Authenticated sender: email@example.com) by ns.cydsur.com (Postfix) with ESMTPSA id 1D985330D3F1; Fri, 2 Sep 2016 13:45:14 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cydsur.com; s=mail; t=1472816717; bh=8OGFi38ZIKFm+jXd0aJbg6pZnAOtjZMC4U8yHU+Tpm4=; h=From:To:Cc:Subject:Date:From; b=OaGmCrOIBLREC3z5kJt4Z91CTK7caJY0FQvYtTQBiJjrAiK4HQw1/LotUW9g7DuZQ SOchVeXw7Filp0smGGOdVnJWrSdHEWT74SwqWTULmpYxIHOds68HOIWwJJKR8rxLOe a+TidmwP93Zua4ETN51zqU/QVtB9I1oefxd0W0B0= From: =?iso-8859-1?Q?XXXXXXXXXXXXXX?= <firstname.lastname@example.org> To: <email@example.com>, <firstname.lastname@example.org> Cc: "'XXXXXXX'" <email@example.com> Subject: RV: ctas de usuarios. Date: Fri, 2 Sep 2016 13:45:16 +0200 Message-ID: <000301d2050f$7a7d3540$6f779fc0$@com> MIME-Version: 1.0 Content-Type: multipart/related; boundary="----=_NextPart_000_0004_01D20520.3E060540" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AdHjLl7+vxyBNVQdQIWvJApRimDm9gh3o/5Q Content-Language: es X-Spam-Status: No, score=-0.7 required=5.0 tests=ALL_TRUSTED,BAYES_00, HTML_MESSAGE,TVD_RCVD_SINGLE,T_KAM_HTML_FONT_INVALID,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on ns.cydsur.com X-Virus-Scanned: clamav-milter 0.98.7 at ns.cydsur.com X-Virus-Status: Clean