Office365 and Comcast

by Dave Michels

My home/office gets Internet from Comcast. We tolerate each other, and do our best to avoid communications. In terms of broadband Internet there really isn’t a viable alternative.

For the most part the service is fine. But when a hiccup does occur it can be painful. I am in that process now.

About two weeks ago my Outlook account on Office365 stopped working. I can no longer send email from Outlook client OR the web portal. It isn’t my primary account, but I do use it and I do pay for it. I called Microsoft for assistance. The technician quickly ascertained the problem was my public IP address. He said that my address has been flagged by Spamhaus, a SPAM service that Microsoft uses. He said my account was in good standing, but I would need to send email from a different IP address and suggested I contact Spamhaus to try to get my address taken off the list.

Now this strikes me as odd. Let me count the ways:

  1. My address is dynamically assigned by one of the largest ISPs in the country. End customers do not have control over their dynamic IP address.
  2. I am paying Microsoft for services that include email. They shut me down without any explanation. The free, Gmail, and Google Apps email services work fine.
  3. Comcast has no ability to deal with this. They don’t consider it an outage , and technically it isn’t. The first level techs do not understand IP addresses. They consider it a Windows problem and offered to transfer me to Microsoft. (the same problem would apply to Macs in the house too).
  4. Spamhaus isn’t useful either. Their website says that I should use Comcast for outbound mail, but that’s not the way Office365 is designed to work. Regarding getting the address removed from the list, the site says: “Removal of IP addresses within this range from the PBL is not allowed by the netblock owner’s policy.”  Basically, Microsoft and Spamhaus are pointing to Comcast. Note: Microsoft is the customer of Spamhaus, not me.


Evidently there are ways to force the modem to get a new IP address. I figure this problem can strike again anytime, so the right answer is to work the system. I am continuing to work the Comcast angle. I have made two 20 minute calls so far. The first was a complete waste of time. The technician followed a script of basic troubleshooting questions which included questions about my operating system. Despite my explanations, she transferred me to Windows support. They transferred me back too 1-800-Comcast. The second call wasn’t much better though she did try harder. She opened a ticket and told me to call the Security group during their operating hours. That will be the third call.

I believe Comcast should provide me a clean, fixed IP address as a resolution. However, I can hear them already saying that as a residential customer I don’t need that and that all of their services are working fine. Microsoft is obviously making a mistake with their filtering procedures and reliance on Spamhaus, but I don’t see that changing because of me.


One of the attractions of cloud-delivered services is outsourced operations. It is the companies with small (or no) IT departments that head to cloud services first. This is a complex issue. I could not figure out why my emails were bouncing at the Office365 server. The Microsoft technician was able to understand it, but unable to fix it. I am stuck  – no email (and that means no Lync Room system),  no champion, and three providers that are pointing fingers at each other. Even if the issue gets resolved at home, it can happen elsewhere likely where I least expect it – Starbucks, in-flight, hotels. Microsoft is filtering based on the user’s address, not the user.

I have considered moving my primary email over to my Office365 account, but this situation terrifies me. Email from Office365 does not seem well thought out in terms of design or support. I did not send SPAM from my IP address. I am using basic ISP services as designed from Comcast and standard services as designed from Microsoft – I am a paying customer for both. If my business was running Office365 via Comcast, I would be seriously hurt by this. Exchange and Outlook are robust and mature products – Office365 is not.