Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

One of the users on my server ( is having trouble sending email to any Verizon accounts. It looks like my server has been blacklisted by them for some reason. The message in the email is: SMTP error from remote mail server after initial connection: host []: 571 Email from is currently blocked by Verizon Online's anti-spam system. The email sender or Email Service Provider may visit and request removal of the block. 110510

There's no unusual levels of mail activity coming from my server, and I've checked all the blacklist sites and the IP does not appear there.

I used the online white request on Verizon's site, and I got this message:

After investigation, Verizon Online Security has determined that e-mail from your IP address will not be allowed access to the Verizon Online e-mail domain due to one or more of the following reasons:

Your IP has been blocked because of spam issues or because your ISP indicates that it is dynamically assigned

No Reverse Hostname associated with your IP address.

As far as I can see this is rubbish... or am I looking in the wrong places?

What other information do I need to be able to diagnose this?

I'm happy to make changes if necessary, but I've no idea where to go next.


EDIT: Might be worth noting that I've tried the removal request 4 times over two months. Same result each time.

share|improve this question
Looks like you do in fact have a reverse lookup hostname on that IP; was that added after they rejected your request? – Shane Madden Jun 15 '11 at 20:39
Nope, been there since server setup! – Lee Jun 15 '11 at 20:40
I see you do have a reverse lookup, you may be blacklisted somewhere you haven't checked yet. – SpacemanSpiff Jun 15 '11 at 20:44
Well, if there aren't any spam issues, then I think all of their reasons are out the window; the reverse lookup is fine and that IP range is clearly a hosting company. An SPF record is the only thing I'd suggest adding, but they didn't mention that as a reason.. Is there any way you can tell them, "you're wrong, look again"? – Shane Madden Jun 15 '11 at 20:46
@SpacemanSpiff I'd love to find someone that I'm listed, I really would. At least I could diagnose if so. I'll take another look around. – Lee Jun 15 '11 at 20:48


It seems it might be coming down to maybe two possibilities:

  • You are on an IP block that is identified as dynamic-allocatable (via a list Verizon is utilizing)
  • Your hosting outfit is hosting someone else who is a spammer

Did you know that "" is sharing your IP?

share|improve this answer

I encountered the same issue. As I mentioned in my comment, I was clean on several large, aggregate blacklist checks (including mxtoolbox and some more comprehensive ones); rDNS was correct; IP was static and was not shared; SPF record was in place; and I'd thoroughly tested as not being an open relay. Despite that, when I used their automated whitelist service, Verizon claimed No Reverse Hostname associated with your IP address which was obviously incorrect.

Therefore I sent an email to their whitelist support address. I won't list it here for obvious reasons, but it's in the information provided at the URL pointed to in the SMTP rejection. I explained all the points I made in my first paragraph.

About a week later, I received a response:

Thank you for contacting Verizon Online Abuse. After a thorough investigation of your issue, Verizon Online Abuse has determined that normal e-mail delivery should be restored within 2 hours.

I resubmitted the queued emails and they went through fine. I haven't had a problem with them since.

share|improve this answer
Upvoted for providing the obvious answer: Contact Verizon. – Ryan Ries Nov 6 '13 at 18:50

The thread on verizon support forum lists necessary steps to open ticket with verizon on this. You need to be verizon customer in some way to be able to post on the forum though.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.