email to sms gateway issues

  • 12 January 2016
  • 54 replies

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54 replies

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Thanks for bringing this to my attention. Many legitimate services share ISP outbound email connections with spammers and unfortunately, was used for mass phishing attack last year. was intentionally blocked because there was a spam attack originating directly from perfora outbound SMTP servers. Normally I try to block specific sources but the attack was widespread across Perfora spamming recipients over 200k messages per day. The attack reluctantly required to block a large block of Perfora IP addresses in the range.

I have unblocked, but if it occurs again, I will be forced to block any mass source of spam. Since spammers rely on this type of breach, they seek IPs that cannot be outright blocked that would impact legitimate traffic use.

Thanks. It works now.

Our SPF records are setup correctly

we are also seeing these 550 errors coming from ‘Exchange Online’.
Is there something they can do to let our traffic through? 

Userlevel 3
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If you could please follow me on my profile, and I follow back in order to send me a PM so that you can provide me with specific message and header details. I can then take a look and determine the exact reason for rejection. I went ahead and followed you. Thanks, Sean.

Sorry to dogpile onto this thread — I too am experiencing a similar issue.

Here's the response I'm getting:

Original-Envelope-Id: <>

Reporting-MTA: dns;

Arrival-Date: Thu, 15 Mar 2018 08:40:21 -0500

Final-Recipient: rfc822;

Action: failed


Diagnostic-Code: smtp;550 permanent failure for one or more recipients ( Sender IP reverse lookup rejected)

I'm sending from
Mind sorting? Note that doesn't host any free email accounts or such, so whitelisting would be optimal 😊

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Header as received:

Received: from ( []) by (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 15 Mar 2018 13:32:51 +0000

Received: (Haraka outbound) with LOCAL id BA44E6C7-8F46-4CA0-9408-3A6F2CD88073.1; Thu, 15 Mar 2018 08:32:50 -0500

Authentication-Results:; iprev=pass; auth=pass (plain)

Received: from users-MacBook-Pro.local ( [])

by (Haraka/2.7.3) with ESMTPSA id BA44E6C7-8F46-4CA0-9408-3A6F2CD88073.1

envelope-from <> (authenticated bits=0);

Thu, 15 Mar 2018 08:32:49 -0500


From: "" <>

Sender IP: (

$ host has address mail is handled by 10

$ dig -x

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.62.rc1.el6_9.4 <<>> -x

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2373

;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0


;  IN      PTR


I cannot whitelist external SMTP clients when the root cause is invalid SMTP server banner mismatch. The outbound MTA for is not matching reverse DNS. The reject message "550 Sender IP reverse lookup rejected" is generated based on presented information from the connecting SMTP. Need to update MX records.

You would need to verify with Fused hosting as to the correct use of SMTP settings.

$ dig txt +short

"v=spf1 +ip4: +ip4: +ip4: -all"


Please visit this tutorial link to read up on why the rDNS is invalid. I dont know if you are using Fuse for hosting service or actually trying to send directly as a branded message or just need help with configuring the SMTP setup. But as configured, this setup is mismatched and will not be permitted by the hosts as per their MX setup.

SMTP      - SMTP Banner Check

SMTP Banner CheckReverse DNS does not match SMTP Banner

$ drill mx

;; ->>HEADER<<- opcode: QUERY, rcode: NOERROR, id: 61419

;; flags: qr rd ra ; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0


;;  IN      MX

;; ANSWER SECTION:      7200    IN      MX      10

Hello, I need to connect you with the person who is the email

administrator. His email is Greg Sellek. can you

please contact him?

thank you,

Erika Ortiz

2018-03-14 15:14 GMT-05:00 srickar <>:

T-Mobile Support

email to sms gateway issues

reply from srickar

<> in *Account

& services* - View the full discussion


Userlevel 5

@magenta4393668​ Hey there!

We don't offer support directly through email, but you are welcome to either file a ticket with a Support representative for the issue you are having, or have your administrator contact us through here. 😊 A T-Mobile account is not required to create a Support account!


Userlevel 3
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Are messages originating from That domain is blocked back in February for spamming T-Mobile. Can you clarify if your messages originate from this domain?

Userlevel 3
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Circling back to send a reminder. I wanted to try and get this taken care of for you. Thanks.

Same issue here, sending SMS notifications through a small business software.


550 permanent failure for one or more recipients (<number>

Starting January 23rd, 2019, there has been a large increase in blocked SMS messages; primarily seeing domain as the blocked sender, but there are many others too.  I don't see a way to add SPF for Gmail.  We are not encountering this issue with any other carrier.

Please advise, as this is extremely urgent. 


Userlevel 3
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Sent you a follow request. Just a heads up, Gmail definitely will not permit another entity to alter the reply-to address while using gmail controlled email servers. Its to prevent spoofing and that's why DMARC/SPF hard/soft fail is common RFC email standard to prevent spoofing of another managed domain entity.

Thank you for your quick reply!

We had Gmail working just fine through January 22nd.  All messages were being successfully delivered.  Starting January 23rd is when all gmail messages began getting blocked.

Userlevel 3
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I followed you and through inbox but I cannot send you a message until you follow me or try sending me a PM. Send me the details such as email headers and source email and I will take a look ASAP.

I am having a similar issue where messages are being blocked

Could you help me fix this issue,  I have requested to follow you and am awaiting your aporoval

Thank. You

srickar, can you help me with this exact issue?

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Userlevel 3
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Yes, definitely. I sent you a follow request earlier this morning. Please follow back through inbox and you can send me a message. Thanks!

Help and thanks for following, what do you need to help me with this issue

Thanks have the rejected email, should I i m forward that to you?

We are a police department with paging system that all of a sudden stopped sending texts to t mobile officers so it's kind of a pressinf issue for us

Thank you

Dennis kitsos

Easton Police Department

Get Outlook for Android

Here is one of the rejected messages. Our paging system was sending the messages directly but they advised us to have us relay from our internal mail server which has correct spf records setup. We have since set it to relay from the email server instead of sending out directly to

Here is the rejected message:

Delivery has failed to these recipients or groups:<>

A problem occurred while delivering this message to this email address. Try sending this message again. If the problem continues, please contact your helpdesk.

The following organization rejected your message: (

Diagnostic information for administrators:

Generating server:<> (

Remote Server returned '< ( #5.0.0 smtp;550 permanent failure for one or more recipients (<>)>'

Original message headers:

Received: from ( id hcems60171s4 for <<>>; Wed, 13 Feb 2019 00:40:12 -0500 (envelope-from <<>>)

Received: from ()

by () (SonicWALL )

with ESMTPS (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256/256)

id o201902130540110039204-21; Wed, 13 Feb 2019 00:40:11 -0500

Received: from ( by ( with Microsoft SMTP Server (TLS)

id 15.0.1320.4; Wed, 13 Feb 2019 00:40:11 -0500

Received: from () by () with mapi id

15.00.1320.000; Wed, 13 Feb 2019 00:40:11 -0500

follow request sent. We are experiencing the same issue.

@srickar​ I am having the same email to SMS gateway blocking issue.  T-Mobile is the only carrier that we have this problem with.  We've done just about everything imaginable on our end to make sure that we have no configuration issues on our end.  Can you please help with the process within T-Mobile to get this resolved?

Userlevel 3
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Please send me a P.M. and I can investigate. Thanks.

@srickar​ My company has a system that has been sending email to SMS for years. Recently our T-Mobile users have been reporting that they have stopped receiving their messages. After reading through several forums now, I believe that our domain has been blacklisted. I was wondering if you could help. I followed you earlier, but I am not able to send you a P.M.

Please email me my monthly statement at @magenta9739608.


Castalia Haynes