Slashdot Mirror

← Back to Stories (view on slashdot.org)

Ask Slashdot: How To Unblock Email From My Comcast-Hosted Server?

Posted by timothy on from the why-not-hand-deliver-those-messages? dept.

New submitter hawkbug writes For the past 15 years, I have hosted my own email server at home and it's been pretty painless. I had always used a local Denver ISP on a single static IP. Approximately two years ago, I switched to a faster connection, which now is hosted on Comcast. They provide me 5 static IPs and much faster speeds. It's a business connection with no ports blocked, etc. It has been mostly fine these last two years, with the occasional outage due to typical Comcast issues. About two weeks ago, I came across a serious issue. The following email services started rejecting all email from my server: Hotmail, Yahoo, and Gmail. I checked, and my IP is not on any real time blacklists for spammers, and I don't have any security issues. My mail server is not set as an open relay, and I use SPF records and pass all SPF tests. It appears that all three of those major email services started rejecting email from me based on a single condition: Comcast. I can understand the desire to limit spam — but here is the big problem: I have no way to combat this. With Gmail, I can instruct users to flag my emails as "not spam" because the emails actually go through, but simply end up in the spam folder. Yahoo and Hotmail on the other hand, just flat out reject the traffic at lower level. They send rejection notices back to my server that contain "tips" on how to make sure I'm not an open relay, causing spam, etc. Since I am not doing any of those things, I would expect some sort of option to have my IP whitelisted or verified. However, I can not find a single option to do so. The part that bugs me is that this happened two weeks ago with multiple major email services. Obviously, they are getting anti-spam policies from a central location of some kind. I don't know where. If I did, I could possibly go after the source and try to get my IP whitelisted. When I ask my other tech friends what they would do, they simply suggest changing ISPs. Nobody likes Comcast, but I don't have a choice here. I'm two years into a three-year contract. So, moving is not an option. Is there anything I can do to remedy this situation?

8 of 405 comments (clear)

  1. Call Comcast? by Pope · · Score: 5, Insightful

    It's a business account, you should have a business support line.

    --
    It doesn't mean much now, it's built for the future.
    1. Re:Call Comcast? by csnydermvpsoft · · Score: 3, Insightful

      There's likely someone else on a nearby IP address with a misbehaving mail server, and your IP address is collateral damage. While they might not be able to fix your problem, the reputation of the IP addresses that they hand out is at least partially your ISP's responsibility.

    2. Re:Call Comcast? by ledow · · Score: 4, Insightful

      Their IP is their management problem. If they were on a spam blocklist, you'd expect to move to another.

      You tell them if you can't send mail from your business account, it's pointless having it.

      Then you terminate the contract because it's now useless and the conditions you can use it under have changed - you can NO LONGER SEND EMAIL.

      Then it's in their court. They can either fix it, or let you out of the contract. If they do neither, you terminate the contract and let them chase you.

  2. Use a relay. by Anonymous Coward · · Score: 2, Insightful

    Stop trying to "fix" comcast. You can't. Find a provider that will act as a relay, which may even be Comcast. Then setup your mail server to relay the mail through that provider.

    You can fix this problem in less than half a day.

  3. Re:Same issue... just relayed all outgoing mail by Anon-Admin · · Score: 5, Insightful

    Ditto! I had the same issue and solved it the same way. Comcast has an SMTP relay that will blanket allow all internal ip's. I simply pointed mine to there smtp relay and it was allowed.

  4. First step is to collect data. by khasim · · Score: 4, Insightful

    He's having problems with 3 services.

    1. GMAIL - messages accepted but marked as spam.

    2. YAHOO - messages rejected (what do the logs say?)

    3. HOTMAIL - messages rejected (what do the logs say?)

    So the first step is to look at the logs and see if the rejection message has any information in it. Do the rejection messages at YAHOO and HOTMAIL have the same code?

    The next step is to check with a service like http://www.dnsgoodies.com/ to make sure that Comcast has configured their side correctly. The reverse DNS should point to your domain. You DO have a domain, right?

    The more information you have before you contact Comcast, the better. Because the first 2 levels won't know anything about anything. They will be reading off of a script.

    1. Re:First step is to collect data. by khasim · · Score: 4, Insightful

      Deferred: 421 4.7.0 [TS01] Messages from XXX.XXX.XXX.XXX temporarily deferred due to user complaints - 4.16.55.1; see

      That seems to indicate that at least one of your recipients at YAHOO is actively flagging your messages as spam. Maybe they have incorrectly written a rule that is doing so.

      Deferred: 421 4.7.1 [TS03] All messages from XXX.XXX.XXX.XXX will be permanently deferred; Retrying will NOT succeed.

      ... and ...

      Deferred: 421 RP-001 (BAY004-MC5F24) Unfortunately, some messages from XXX.XXX.XXX.XXX weren't sent. Please try again. We have limits for how many messages can be sent per hour and per day.

      And that one seems to be saying that your IP address is sending too many messages.

      How many messages per day are you sending?

  5. The don't give a Flying-F*** about your SPF by tlambert · · Score: 1, Insightful

    The don't give a Flying-F*** about your SPF if your DKIM is wrong or if you are using an @yahoo.com email address.

    What they care about is that they've updated their DMARC record to reject @yahoo.com emails in the From: address if they aren't sent by yahoo.com servers.

    You should have googled this.

    https://help.yahoo.com/kb/mail...