MS Azure IPs blacklisted

Question

Dear Support Team,

e-mails sent via my Office 365 account from the app in MS Azure get rejected by receiver's incoming mail servers. It's caused by the fact, that originating IP address belonging to MS Azure is blacklisted in spamhaus (for example 104.46.52.73). What do I have to do in order to make sure the e-mails will reach recipients?

Kind regards,

Tomasz

Answer 1

Are you sure it's Azure IP?

When you send email with O365 account, email should go over O365 SMTP as Azure doesn't allow use of local SMTP. So, I think problem is with Office 365 IP address, not Azure.

---

Mustafa Toroman, Azure MVP

Answer 2

I'm getting the following response:

Delivery has failed to these recipients or groups:
my-email<at>gmail.com
Your message wasn't delivered because the recipient's email provider rejected it.

Diagnostic information for administrators:
Generating server: AM5PR1001MB1058.EURPRD10.PROD.OUTLOOK.COM
[e-mail]
Remote Server returned '550 5.7.501 Service unavailable, Client host blocked using Spamhaus. To request removal from this list see http://www.spamhaus.org/lookup.lasso (AS16042849)'
Original message headers:
Authentication-Results: gmail.com; dkim=none (message not signed)
 header.d=none;gmail.com; dmarc=none action=none header.from=mydomain.com;
Received: from RD00155D49BC06 (104.46.52.73) by
 AM5PR1001MB1058.EURPRD10.PROD.OUTLOOK.COM (2603:10a6:203:12::17) with
 Microsoft SMTP Server (version=TLS1_2,
 cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1220.11; Tue, 27
 Jun 2017 07:52:26 +0000
MIME-Version: 1.0

From: no-reply<at>mydomain.com
To: my-email<at>gmail.com
Date: 27 Jun 2017 07:52:25 +0000
Subject: Confirm your account
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: quoted-printable
X-Originating-IP: [104.46.52.73]
X-ClientProxiedBy: VI1PR0102CA0020.eurprd01.prod.exchangelabs.com
 (2603:10a6:802::33) To AM5PR1001MB1058.EURPRD10.PROD.OUTLOOK.COM
 (2603:10a6:203:12::17)
Return-Path: no-reply<at>mydomain.com
Message-ID:
<[e-mail]>

Answer 3

And ipwhois results for 104.46.52.73:

104.46.52.73 - Geo Information
IP Address     104.46.52.73
Host     104.46.52.73
Location     NL NL, Netherlands
City     Amsterdam, 07 1091
Organization     Microsoft Azure
ISP     Microsoft Corporation
AS Number     AS8075 Microsoft Corporation
Latitude     52°35'00" North
Longitude     4°91'67" East

Answer 4

It is MS address and Office 365 as SaaS is also hosted in same datacenters as Azure.

Still this isn't problem with Azure but with Office 365 and you should contact O365 team for this.

To verify, try sending mail to same address using same account with OWA or Outlook, you shoud get same report.

---

Mustafa Toroman, Azure MVP

Answer 5

I've sent some e-mails via online outlook and they have always reached recipients. It looks like different IP is used in that case.