I am suddenly having issues getting email delivered to charter.net and rr.com, which are both part of spectrum. I don’t know if the block is based on domain or ip or maybe a block of ips. I’m asking here on the off chance that a block on DO IPs got blocked for some reason.

SMTP via Posfix on CentOS

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  • So my concern here has started to move toward panic. We just got blocked by the msn.com and hotmail.com. The message clearly states that a range of addresses at our ISP are being blocked rather than an issue that is specific to our email sending. When I check our logs, outbound to msn.com and hotmail.com is small, but even one password reset confirmation not getting through is enough to be a problem. We have no problems for years and now we have encountered a couple of major blocks within the last few weeks. Has anybody else noticed a significant increase in email deliverability problems recently? Does DO have something significant going on here?

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yep, that is the standard message charter is sending for too much mail from a range of addresses under the same ISP that they don’t like. Most of the other email providers at least put the word “range” into the message, but charter seems to be happy sending us on an endless chase to try to convince them that we are not sending too much mail.

There really is no way to get unblocked at Charter right now. I had one address that worked and 5 others that didn’t, but there is no way to know when more addresses might get added to the blocked range.

I believe the only way to have this fixed at DO is for DO to isolate a set of addresses for outbound email and then allow us to request them with an explanation of what email will be sent. But then DO would need a way to shutdown or punish offenders and that is more overhead on them.

So… sendgrid or aws sms or one of the other services out there. The situation is way beyond frustrating....

  • So how is it that sendgrid and aws sms (etc.) don’t get flagged for email abuse?

    This sounds like an business opportunity for Digital Ocean. We already using them for services hosting, load balancing, storage, etc., etc., … why not email?

    More vendors = more complexity to running my business and operations.

Hey friend!

Honestly, they block a good portion of hosting company IPs from sending them email. It’s pretty hit or miss, and even if you get through on an IP one day it might be blocked the next (especially if you ever forward email, which ensures the delivery of spam). Some major SMTP services like SendGrid (just one example) might have better luck on average than going at it alone.

I know that doesn’t offer a quick fix but this is something I’ve seen so many times that I’ve kind of given up on the idea that a quick fix exists for this particular situation. I hope my perspective was at least helpful :)


SendGrid has a great service, but at some point we had decided to just handle it ourselves. You’re right though, sending email is easy but actually getting it delivered is an ongoing challenge.

So a few more items to help add context:

  • We don’t forward any emails.
  • We do send email on behalf of clients. If they have an SPF record in place we allow a from email address using their domain. If they don’t have an SPF record in place, we send under our domain with a reply-to set to their domain. Our clients are all non-profits and they only send email to their membership, so there shouldn’t be much unexpected mail.
  • We have DKIM signing in place and working.
  • Mail reputation is high
  • no black lists
  • I have a clean report on mxtoolbox, other then it doesn’t like the SO records for DO DNS.
  • I check the logs and the only bad email we ever sent was a unknown address because of a typo when it was entered, and there is only a hand full of those.

It takes a lot to try to keep the email reputation high and then suddenly I this back…

(host mx1.charter.net[] said: 452 4.1.1 Too much mail from this address E2210 (in reply to RCPT TO command))

And just to add some perspective to that, I don’t think we’ve ever gone over 50 emails to charter.net in a day with a smtp concurrency limit set to 1 with 10s delay. Too many??

I’m a little frustrated :-)

Look at your bounce e-mail. Often there will be instructions for getting off of their bad list. Back when I was on shared hosting, I had to go through the hoops to get my e-mail going through to different mail servers. I did not wait for the host to take care of it, I took care of it myself, and even though I was not the administrator of the shared server, I was always able to get it fixed.

Does the bounce e-mail give any info?

Wayne Sallee

Also make sure that your MX record ends in “-all” and not “~all”.
This tells other servers to discard any e-mail pretending to be from you but not sent from your server.

Wayne Sallee

I know this is a month old thread, but I have been having the same problem for around that month now. Charter tells you to create a new email and attach the body of blocked emails to ’unblock@charter.net’ for their review. When you send the report, as they request, that email is also blocked because it’s from the blocked domain or IP. So, you create a new email from a different address and send that, but get no response or action from them. I called their 800 line and went four or five techs deep until I got a supervisor who refused to even get on the phone with me to discuss. They would not help me because I am not their customer. Their answer? The customer has to call them. That means contacting the recipient of an email, in this case a receipt from an online store, and ask them to call on your behalf to get your server unblocked, probably spending hours on the phone with them. It’s just stupid, and shows how little these ISPs care about their own customers, let alone anyone else. I never thought I would see someone worse than Comcast. Spectrum and Charter are certainly making a strong case.

  • I guess I’m “lucky” because I am also a Charter customer and have been for many years. I opened a ticket stating that my own business cannot send mail to my personal charter address because charter has it blocked. So far the consider me a spammer, a lier and incapable of administering my own server… but they are still willing to accept my monthly payment for internet and cable TV access.

Still fighting the battle and could use a little input on postfix.

I pulled my postfix logs for the days leading up to the “block” from charter.net, filtered to smtp and error processes and I can see no more than 20 connections to charter.net per hour. Charter insists that I am sending in excess of 600 per hour. When I shared my data they recommended I have geek squad look at my device because somebody is getting through my firewall and sending from my IP address. My assertion would be that if somebody is using my server as a relay, I would see the outbound smtp connections in the postfix log? Is this a valid assertion?

And while on the topic of postfix, I have:

smtpd_recipient_restrictions = permit_mynetworks
virtual_alias_domains = mydomain.com
virtual_alias_maps = hash:/etc/postfix/virtual

Which I believe should allow allow connections from addresses explicitly listed in mynetworks or that are sending to addresses listed in virtual. Is there something I am missing here?

  • Could be those 20 connections are sending multiple emails to multiple different people each. Spammers usually use cc or bcc to send to dozens at a time. You would likely see that in the log though. A script that has been compromised could also send through php without needing authentication which could bypass logs.

From what I can tell, the 20 connections are mine and are expected.

How would it bypass the postfix logs? You are thinking I have a PHP script doing a direct SMTP connection?

I don’t even know how somebody would trigger that. I only have port 25, 4444 and 443 open. I use 4444 for ssh and it only allows connection with a certificate, 443 would be apache and I would see something burping out of that. 25 is postfix and I described that config above.

I guess I could use netstat or something similar to double check outgoing connections.

It seems remarkable that nobody else would be complaining. But, unlike Charter, I am open to the possibility that I am wrong or that I missed something.

I was just informed by Spectrum engineers today after spending 2 weeks/16 hours on the phone trying to address this same problem that they have supposedly blocked 100% of Digital Oceans ip addresses and do not allow individual whitelisting for any ip address under the “Digital Ocean Umbrella”..

If the mail server resides on a Digital Ocean equipment they say its permanently blocked..

Is there anything digital ocean can do to help here? Sendgrid isn’t inexpensive, so this will essentially double my hosting costs by adding send grid to my infrastructure. The other choice is to look at other hosting, but I suppose I could easily hit the same issue in other places as well.

Is there some bad blood between DO and Spectrum?

  • I was just told that because of the massive amounts of spam reported coming from Digital Ocean servers in the past and currently they they have just put a blanket ban on Digital Ocean.
    The IP that I was given when I signed up for Digital Ocean was on numerous blacklists,etc… and it took me a bunch of effort to clear that up with many carriers/ISPs,etc…
    I guess this is just another reason to pay up for email hosting/management.
    Try to do it on your own and get screwed by the big guys..
    Its quite a task keeping up with all the blacklists/blocks/reputations,etc…

    Assuming what I heard is true (and so far it seems like it as I have had other Digital Ocean users try to send me emails to my personal Spectrum account and they are all bouncing back too..) I was really hoping that Digital Ocean could do something about this as a company wide blacklist is certainly not good for their business.. Its likely causing me to move on..

I’ve been struggling with both Spectrum and Microsoft for about a month or so now, too. I host a small site for a non-proft that I’m part of on a Droplet that I otherwise use for personal hosting. I run a few mailman lists for the organization that we use to send maybe 200 emails/week to our members, if we’re lucky. I’ve been doing this for a few years and have become quite familiar with all the mail-related acronyms: RDNS, SPF, DKIM, DMARK, and everything is in order and the server itself is not blacklisted anywhere that I can find.

With our predominant local ISP being Spectrum (formerly Time Warner), we have lots of members using their RoadRunner email accounts, which was the first ISP where I noticed issues. Unfortunately the error message Spectrum returns is simply “SMTP server unavailable,” which is completely unhelpful, especially when I can send from another (non-DO) email address with no problems whatsoever.

I am a Spectrum customer myself, so I have an email address with which to test. I’ve tried reaching out to support, but I get nowhere. Emails to various postmaster@, ubblock@, etc. addresses either bounce or go unanswered.

What cued me in to where the problem actually lies was when hotmail and outlook.com mail started bouncing. Microsoft provided a bit useful bounce error message indicating that we were blocked because of a wider block on a range of IP addresses. With some searching, I came across this form, and I got an email within less than 24 hours indicating that we were “conditionally unblocked.”

Spectrum is still an issue. I’m now thinking that I may move the non-profit’s site onto a server I have with a different host to see if that makes a difference. I don’t want to do that as the DO server has better resources, but not being able to send email to Spectrum, as much as I want to tell all of our members to switch to something better, is a real deal breaker. We have no real budget for web/email services, so going to a dedicated email provider really isn’t an option for us.

I want to add a status update for others that have run into similar problems.
We spent a lot of time with an executive escalation on Spectrum and in the end the problem is as a few others have explained, Spectrum has blocked ranges of IP addresses that cover much of DO’s address space and they will not unblock any of these addresses until DO “get’s their problem under control”. On the other side equation, DO cannot justify the mail coming from every address that they own, so they cannot meet Spectrum’s demands. As much as I would like to blame Spectrum for their heavy handed practices or DO for not keep the spammers out, we all know that the problem is really with the spammers and phishers that are making it so difficult for any of us to send mail.

I went back and looked at sendgrid again and am currently sending mail through an “essentials” account for $9.95 a month. I still find their price for a dedicated IP too high, at $79 a month, but the essentials account is actually working pretty well right now. They are easy to work with and they also have a free plan if you are not sending a lot of mail.

I am also looking at Amazon’s Simple Email Service (SES), but it more complicated than using sendgrid. The only advantage I see right now is that a dedicated IP address is only an extra $24 a month.

Since I’m a Spectrum customer, I came up with a workaround. I created a new email RoadRunner email account for my server and set up msmtp to send mail through it. Then I set up a router in Exim that directs messages bound for our local RoadRunner domain to msmtp via a pipe, so that those messages are handed off over an authernticated connection. This process bypasses my DKIM signing and would fail SPF validation, but Charter doesn’t seem to care, and my users are getting their messages again, so I’m happy.

If I wasn’t a Charter customer, I could probably do something similar with another email provider, though in that case I’d probably have updated my anti-spam DNS settings.

host mx1.charter.net[] said: 452 4.1.1 Too
    much mail from this address E2210 (in reply to RCPT TO command)

Final-Recipient: rfc822;redacted@charter.net
Original-Recipient: rfc822;redacted@charter.net
Action: failed
Status: 4.1.1
Remote-MTA: dns; mx1.charter.net
Diagnostic-Code: smtp; 452 4.1.1 Too much mail from this address E2210

How much is “too much mail”?

I’m pretty darn certain no one is using my server to SPAM (I would have heard of it). We do a bulk email at most once a month, and we send out probably a dozen or so sales receipts to Charter (likely much less).

Same problem here with roadrunner. Emails are blocked by charter.net
Only solution found: create a gmail account, add your own email address in gmail, and use the gmail smtp to send emails. The From: will be your own email (not gmail).
I guess DO is not the right choice anymore.

  • I was very frustrated by this at first and even considered a move to AWS because of it. But, if you look at sending email from your EC2 instance you will see that there are limitations put in place by AWS. You can use AWS’s simple email service (SES), but that isn’t much different than using DO and sendgrid or sparkpost. In fact, I found that in my situation sparkpost was actually less expensive and easier to implement than SES.

    I’m not terribly frustrated with DO at this point, but I am frustrated at the spammers that have made things so difficult for those of us that want to send email for legitimate reasons.

seems that we are affected by this too. Is DigitalOcean able to do anything to assist us? I’ve already reached out to charter/specturm with no response.

I submitted a ticket to Digital Ocean and was essentially told it’s probably best not to run my own mail server. They won’t do anything to help. I’m less than thrilled with this response, since I’ve been running secure mailservers for the last 8 years with Rackspace, and had no problem getting bad IP’s delisted until moving to DO.

But, I’ve also not even found a way to REQUEST a delisting through charter/spectrum. There’s nothing on the message except that their server won’t talk to me. No email address, no redress instructions, nada. If anyone has successfully spoken with Spectrum, I’d like to know how.

This is just another reason no one should ever use ISP email. They pretty much universally suck. Not to mention transferring your mail is a pain if you have to switch ISP’s.

  • We went through a lengthy escalation with Charter/Spectrum management. Being a charter customer, we even upgraded our residential service to business service after being told we would get more assistance. The end result is that Charter/Spectrum will not white list any IP address and that they have, in fact, range blocked a large portion of DigitalOcean’s ip addresses. They will not remove this range block unless Digital Ocean manages the outbound mail for each of the IP addresses that is being used to send mail. Trying to explain cloud hosting works was pretty much useless.

    We first tried sendgrid for outbound email and then finally landed on sparkpost. Either service has free options for low volume email and then paid options as the volume and/or requirements for dedicated IP addresses goes up.

    I was pretty stubborn about continuing to maintain control of my own outbound email, but I should have made the move earlier.

It might be a general email deliverability problem - you can run a test with mailgenius.com and see if something is off with your technical setup and authentication.

  • If the question is specific to Charter/Spectrum there is a good chance that the IP address is blocked. Charter/Spectrum told us this as a fact, there is no guessing about what is going on. We have one address out of 12 right now that can send email to charter. I thought about trying to route my charter email through that specific address, but there is no telling when this will get sucked up in a blocked range of addresses.

And the battle rages on…
I consider having a private sending ip address essential to managing our sending reputation. We started with SendGrid, but the price went to $79 a month for any account that would support a private address. We moved to SparkPost, but now they are raising their prices from $29 a month (for my 50k messages and a private address) to $75 a month. We pay about $80 a month to host our application on DigitalOcean, so maying the same amount to simply send email seems ridiculous. I guess it’s time to try AWS.
Would love to get some help here from DigitalOcean because putting customer in a position where they have to use an AWS service just doesn’t seem right. Couldn’t a block of addresses be set aside for outbound email and those addresses limited to longer term lease and some level of management so they are not abused and sent back to the pool?

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