Our server has recently experienced this problem(2016-11-28). [Branched from an earlier post] We use postfix to send email. How can we find out if our IP is being blocked and how to unblock it ?
Here is an example mail.log message with the phone number Xed out. I can privately provide the actual message with phone number, but not on this public site.
Nov 28 13:23:51 *myserver* postfix/qmgr: F2D4847BA9: to=<XXXXXXXXXX@vtext.com>, relay=none, delay=286868, delays=286868/0.05/0/0, dsn=4.0.0, status=deferred (delivery temporarily suspended: host smtpin02.vzw.a.cloudfilter.net[126.96.36.199] refused to talk to me: 554 vzw-ibgw-6003a.stratus.cloudmark.com cmsmtp ESMTP server not available - POL110 - BRWXcHtnuJp18)
Until recently this has been working flawlessly for a decade or longer.
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I understand the importance of ensuring these messages reach their destination, monstermac77. I appreciate all the information you have provided. I did some digging, and found we had previously implemented a Sender Policy Framerwork (SPF) policy. If your domain does not have a SPF record, some recipient domains may reject messages from your users because they cannot validate that the messages come from an authorized mail server. SPF records are controlled by the owner of the domain of the sender as showing in the SMTP headers. We recommend customers forward this information to the owner of the message-originating domain who actually sends the message to MDN@vtext.com so they can create a SPF record, which lists the mail servers authorized to send these messages.
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I have the same problem. I found that it works from my Linux server (RedHat 5) but not from a Windows 2012 R2 server with Whats Up Gold. As an experiment from the Linux I telnet smtpin01.vzw.a.cloudfilter.net. 25 and type Sendmail command and got a text. When I tried from the Window server I connect but get "554 vzw-ibgw-5002a.stratus.cloudmark.com cmsmtp ESMTP server not available - POL110 - BTXRcrx2CW2dg". The same message you are getting. So in my case it seem to be some type of window issue. I also tried from RedHat 7 which uses postfix. I did not work but it is configuration on my end I think. I did contact the Verizon server which send a legit reject message.
It had been working from my windows server up till 11/22 abouts.
We're experiencing the same issue, which started only very recently (11/10, but really ramped up on 11/20). We also have been using the @vtext.com gateway for 4 years without a single instance of this issue, or any others with deliverability, until now. Since 11/10, over 2000 of our messages to Verizon customers have failed because of this. We really need a fix ASAP. Very happy to help troubleshoot.
We're getting back: "550 5.1.0 <[our email]> sender rejected".
To Verizon: I'm happy to provide any specifics you need (the emails we're sending from, the numbers that have failed, the messages we've been sending, etc.) in a private setting.
You are getting a different error than we are and I think I know how to fix your issue. I think your issue is the domain name in the email. I tested one of my other services that was Redhat 7 and was using postfix. It had the error you said you are getting " 550 5.1.0 <[user@server].localdomain> sender rejected". I fixed the configuration to have our actual domain instead of localdomain and it work. On postfix you edit mail.cf and add myorigin = [your server].[your domain]. if you are using something else you will need to figure out how to get the domain set.
Thanks for your response. That's a good thought, but unfortunately our domain configuration is correct (not localdomain). Considering we all started experiencing these issues around the same time and in at least my and haller.r123's case after not experiencing issues for many years, I'm guessing something changed on Verizon's end. Perhaps their spam filtering, considering we're getting rejections from "....cloudfilter.net" which may be from this email filtering service? http://www.mailprotector.com/cloudfilter/
I'm experiencing the same issue in my domain, and it started about 11/12 or so. Despite being located in Washington state, we are a subsidiary of a Taiwanese corporation, so all our e-mail routes through a mail gateway in Taipei. We figured the problem was that Verizon (or Cloudmark) had decided to block messages form IP addresses in the "Chinese" range. I tried filling out the forms for Verizon and Cloudmark for whitelisting of IP's, but the response I got back was that our IP was not being blocked or spam-filtered. I tried sending an explanatory e-mail to email@example.com, but haven't heard back as of 24 hours later.
If anyone makes a breakthrough on this issue, please post it here so that other e-mail admins googling this problem can find it. I promise to do the same if I stumble on something.
I have the same situation. My mail server supplies the following error message:
The last attempt to send the message was at 11/29/2016 10:50:46 AM (UTC-08:00) Pacific Time (US & Canada) and generated the error '451 4.4.0 Primary target IP address responded with: "554 vzw-ibgw-6002a.stratus.cloudmark.com cmsmtp ESMTP server not available - POL110 - BnUNcwEmoSGWs." Attempted failover to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts.'.
Seems like vtext.com is forwarding to cloudmark.com but is not providing an enhanced SMTP service to receive the message.
I fixed the POL110 problem. I had some servers that worked and some that did not and I realized that the ones that worked had reverse DNS. I had the DNS group add reverse DNS for the ones that did not have it and they now work. So you need both a forward and reverse DNS for your server that is contacting Verizon vtext.com server.
I speculated that POL110 stands for something like Policy 110 since it is not a standard SMTP result message.
As for those having an rejection error I can not say for sure but it might be that your forward and reverse DNS entries for your server may not match or the FQDN your machines gives the vtext server does not match the domain in the reverse DNS. Or maybe something else but it is probably a good chance it has something to do with FQDN not matching.
Also I tried opening a ticket with Verizon unsuccessfully via my sales support person. He though they were end of life vtext.com but I think he just got mixed up with them shutting down the TAP (modem dial up) interface. At any rate there is a API that uses REST to send text but I have not tried it yet.
In our discussions with Verizon, they said that they're currently phasing out @vtext.com, and we should use @vzwpix.com instead. We've changed a portion of our messages to use @vzwpix.com, but we are still receiving some failures (the same response from their server). Anybody else try this?