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Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Regular Contributor

Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

I have been using Cloudflare DNS for the past 4 months without any problem. I have my router, Win 7 PC and Android phones all configured to use it.

But for the past few days, I was no longer getting any of my Comcast.net email on my PC or Phones (when connected through the router with Cloudflare DNS). My other non-comcast email continued to work fine.

I tested my phone by connected to AT&T LTE and it was able to check my Comcast.net emails. Or if I remove the Cloudflare DNS from the router and PC, then the phone and PC can check the Comcast.net email.

 

It seems to me that after 4 months of no issues, that this may be intentional on Comcast for them to "force" people not to use Cloudflare?

 

Tonight I changed everything over to Google DNS 8.8.8.8/8.8.4.4 and that works just fine with Comcast.net email.

Highlighted
Regular Contributor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1


@FAUguy wrote:

I have been using Cloudflare DNS for the past 4 months without any problem. I have my router, Win 7 PC and Android phones all configured to use it.

But for the past few days, I was no longer getting any of my Comcast.net email on my PC or Phones (when connected through the router with Cloudflare DNS). My other non-comcast email continued to work fine.

I tested my phone by connected to AT&T LTE and it was able to check my Comcast.net emails. Or if I remove the Cloudflare DNS from the router and PC, then the phone and PC can check the Comcast.net email.

 

It seems to me that after 4 months of no issues, that this may be intentional on Comcast for them to "force" people not to use Cloudflare?

 

Tonight I changed everything over to Google DNS 8.8.8.8/8.8.4.4 and that works just fine with Comcast.net email.


I appologize, but could you please refresh my memory of how Clould Flare works and why Comcast possibly not want subscribers to use it?

New Poster

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

I am having the same issue with downloading shows from the xfinity app. I use the cloudflare DNS on my router, and it will not allow me to do anything in the app while I'm on Wi-Fi. If I use a different wi-fi system that does not use cloudflare I have no issues. Or if I use my mobile connection I also have no issues. I guess now that net neutrality is gone Comcast is really trying to stick it to us.
New Poster

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

I also recently ran into challenges with Cloudflare. In my case, email worked fine but I couldn't access any streaming content at all from may main computer - every time I accessed Xfinity stream I recieved a message saying to clear my cache. Spent a few hours on the phone with support until I remembered I switched to Cloudflare DNS years ago. Switched to Google (8.8.8.8) and it fixed it instantly. Switched back and streaming was dead.

 

Not knowing enough about it, it seems really odd that email for one person is blocked while streaming is blocked for another.

Frequent Visitor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Thank you for posting this!  I've been banging my head against the wall with support (both Twitter and phone support) trying to figure out why, after the last app update of Xfinity Stream, I was no longer able to use the app (or even log into it.)

 

I set my DNS settings back to automatic on my router and it was an instant fix.

 

Anyone know if this is intentional?  A change that Cloudflare needs to make on their end?

 

Trying to get an update from @ComcastCares support now.

Frequent Visitor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Comcast doesn't know anything about known issue with Cloudflare DNS services.  Most likely this is a problem on Cloudflare's end.  I have a support ticket open with them. 

 

I suggest you do the same to bring better visibility to the issue.

 

https://support.cloudflare.com

Regular Contributor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

I just find it weird that I had no iussue using Cloudflare DNS with checking my comcast.net email accounts the past 4 months, and then just this past weekend it wouldn't work.

I don't use the Stream app, so wasn't aware there was a problem with it as well.

But since changing to Google DNS 8.8.8.8 / 8.8.4.4 everything is working.

So it's a compatibility issues that just recently started, but who is at fault...Comcast or Cloudflare.....it's hard to say.

Regular Contributor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Here is something else I just noticed when using the Google DNS 8.8.8.8 or the OpenDNS 208.67.222.222 is that I can't get the Newegg.com site to load.

But if I use Cloudflare or no DNS setting (which defaults to Comcast DNS) then Newegg will load.

Official Employee

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

We see the problem with DNS resolution you are reporting and are investigating.


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Official Employee

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

We engaged Cloudflare and the issue has been corrected.


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Frequent Visitor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Been beating my head into the wall all day trying to figure out why I'm not receiving emails, then I found this thread. Re ComcastDNS's ‎08-29-2018 11:36 AM msg that the Cloudflare problem has been corrected ... not so sure. Still no emails for me as of 08-29-18 14:45 PDT.

 

Thunderbird gives me a msg saying "Failed to connect to server mail.comcast.net". If I remove 1.1.1.1 from my router and let it default to Comcast's DNS, I get emails. Changing it back to 1.1.1.1, and  doing a "ipconfig /flushdns" command, gets the error msg again. I've got Thunderbird set up as a POP3 acct.  Strangely using an Imap acct with 1.1.1.1 works. Please look into this again. Thx

 

Frequent Visitor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Confirmed that my Xfinity Stream iOS app is now working with my router configured to use Cloudflare DNS servers.

Frequent Visitor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Comcast...please check again.  As of 01:43hrs ET, 1.1.1.1 & 1.0.0.1 will not resolve mail.comcast.net.  If I change my DNS back to what is supplied from DHCP, it works fine.   See example below...

 

Check this out as well...

 

My router is using Cloudflare's DNS:

 

C:\Users\along>nslookup
Default Server: RANSWVTHDR0.lan
Address: 192.168.10.27

> server 1.1.1.1
Default Server: one.one.one.one
Address: 1.1.1.1

> mail.comcast.net
Server: one.one.one.one
Address: 1.1.1.1

*** one.one.one.one can't find mail.comcast.net: Server failed
> server 8.8.8.8
Default Server: google-public-dns-a.google.com
Address: 8.8.8.8

> mail.comcast.net
Server: google-public-dns-a.google.com
Address: 8.8.8.8

*** google-public-dns-a.google.com can't find mail.comcast.net: Server failed
> server 75.75.75.75
Default Server: cdns01.comcast.net
Address: 75.75.75.75

> mail.comcast.net
Server: cdns01.comcast.net
Address: 75.75.75.75

*** cdns01.comcast.net can't find mail.comcast.net: Server failed
>

 

==============================================

 

Changed my router's DNS to Comcast supplied via DHCP:

 

C:\Users\along>nslookup
Default Server: RANSWVTHDR0.lan
Address: 192.168.10.27

> server 1.1.1.1
Default Server: one.one.one.one
Address: 1.1.1.1

> mail.comcast.net
Server: one.one.one.one
Address: 1.1.1.1

Non-authoritative answer:
Name: mail.comcast.net
Addresses: 2001:558:fe21:2a::7
2001:558:fe16:1b::13
96.114.157.77
68.87.20.9

> server 8.8.8.8
Default Server: google-public-dns-a.google.com
Address: 8.8.8.8

> mail.comcast.net
Server: google-public-dns-a.google.com
Address: 8.8.8.8

Non-authoritative answer:
Name: mail.comcast.net
Addresses: 2001:558:fe21:2a::7
2001:558:fe16:1b::13
68.87.20.9
96.114.157.77

> server 75.75.75.75
Default Server: cdns01.comcast.net
Address: 75.75.75.75

> mail.comcast.net
Server: cdns01.comcast.net
Address: 75.75.75.75

Non-authoritative answer:
Name: mail.comcast.net
Addresses: 2001:558:fe21:2a::7
2001:558:fe16:1b::13
96.114.157.77
68.87.20.9

 

Everything works fine. 

 

Please advise!

 

Surfboard SVG2482AC

Regular Contributor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1


@ComcastDNS wrote:

We engaged Cloudflare and the issue has been corrected.


The problem has NOT been fixed when using the mail.comcast.net POP3 E-Mail server (see error below), but is working for the imap.email.comcast.net IMAP E-Mail server.

 

@Unable to send or receive messages for the @comcast account. The host 'mail.comcast.net' could not be found. Please verify that you have entered the server name correctly.

Server: 'mail.comcast.net'
Error ID: 0x800CCC0D
Protocol: POP3
Port: 995
Secure(SSL): Yes
Socket Error: 11004

Official Employee

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Cloudflare's temporary fix improves things, but leaves 6% of queries failing.  Not clear if that's by time or location.  They're working on complete fix.  In the mean time, you may want to use another set of resolvers.      


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Official Employee

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1


@ComcastDNS wrote:

Cloudflare's temporary fix improves things, but leaves 6% of queries failing.  Not clear if that's by time or location.  They're working on complete fix.  In the mean time, you may want to use another set of resolvers.      


And to be clear for other customers reading this thread: this issue is specific to Cloudflare and is due to a technical issue on their resolver platform. We are not aware of this affecting any other DNS resolvers. They are working on it and we're available to help them validate the fix if needed (it likely affects other domains as well). :-) As noted above, if you use a different resolver things will work fine.

JL

I am an Official Comcast Employee.
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Regular Contributor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1


@ComcastDNS wrote:

Cloudflare's temporary fix improves things, but leaves 6% of queries failing.  Not clear if that's by time or location.  They're working on complete fix.  In the mean time, you may want to use another set of resolvers.      


Any idea when Cloudflare will be working again with the mail.comcast.net POP3?

Frequent Visitor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Looks like it's working for me.

 

C:\Users\nope\>nslookup mail.comcast.net
Server:  one.one.one.one
Address:  1.1.1.1

Non-authoritative answer:
Name:    mail.comcast.net
Addresses:  2001:558:fe16:1b::13
          2001:558:fe21:2a::7
          68.87.20.9
          96.114.157.77

 

Try an ipconfig /flushdns and try again?

 

Otherwise you'll just need to wait for the changes to propogate to all other resolvers.  I'm located near Portland, OR, for what it's worth.

Regular Contributor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

I checked it today, and Cloudflard DNS is now working with mail.comcast.net POP3.

Frequent Visitor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Confirmed working here as well.  Let's keep our fingers crossed it does not break again.  I'm out.

Regular Contributor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1


@jlivingood wrote:

@ComcastDNS wrote:

Cloudflare's temporary fix improves things, but leaves 6% of queries failing.  Not clear if that's by time or location.  They're working on complete fix.  In the mean time, you may want to use another set of resolvers.      


And to be clear for other customers reading this thread: this issue is specific to Cloudflare and is due to a technical issue on their resolver platform. We are not aware of this affecting any other DNS resolvers. They are working on it and we're available to help them validate the fix if needed (it likely affects other domains as well). :-) As noted above, if you use a different resolver things will work fine.


New problem:

Now the Comcast Android Apps (My Account, Connect home phone, TV Remote, Stream) are not being able to login when connected to Cloudflare via home WiFi, also the idp.comcast.com is not allowing web browser to login to the Forums page.

 

Update: I've also now seen that on my PC that the speedtest.xfinity.com site will not load while using Cloudflare DNS.

Official Employee

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Unclear why there would be issues using any resolver.  It would be helpful to know where you are, to get more details on the failures you’re seeing, and whether changing resolvers (say, trying our 75.75.75.75 and google’s 8.8.8.8) fixes things.  Lookups for idp.comcast.net and speedtest.xfinity.com across our footprint to 1.1.1.1 look to resolve without issue. 


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Official Employees are from multiple teams within Comcast: CARE, Product, Leadership. We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Mark the post as Best Answer!
Regular Contributor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1


@ComcastDNS wrote:

Unclear why there would be issues using any resolver.  It would be helpful to know where you are, to get more details on the failures you’re seeing, and whether changing resolvers (say, trying our 75.75.75.75 and google’s 8.8.8.8) fixes things.  Lookups for idp.comcast.net and speedtest.xfinity.com across our footprint to 1.1.1.1 look to resolve without issue. 


I am located in the Pompano/Deerfield FL area.

I just double checked, and the issues that I listed are still present. On my PC or Phone (WiFi) connected to my Router and using Cloudflare 1.1.1.1, I cannot login to the forums.comcast.com site, the xfinity.speedtest.net site will not load, and the Comcast Android apps will not log in.

 

But if I remove the Cloudflare 1.1.1.1 and change to either the Comcast or Google DNS, I am still having the same problem.

The only way I can access this forum is to login is with my phone and use LTE connection. As if I use my home WiFi with phone, or wired PC to Router it will not allow any Comcast account login.

Regular Contributor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

Ok, so this is weird, even thought I've tried different DNS servers with my Router and have restarted it, which didn't fix the problem - I just reset my Netgear CM600 modem, and now the Comcast logins are working.

Frequent Visitor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

No issues here since the original problem was resolved.  This sounds like a single user event from that one device.

Regular Contributor

Re: Comcast E-Mail issues with Cloudflare DNS 1.1.1.1

The email issue that I started this thread with, Comcast said the problem had turned out to be with Cloudflare DNS resolver having an issue with Comcast's email server, and that Comcast had to help them resolve it. Though the details were not clearly posted by Comcast.

 

So yesterday when all of a sudden I couldn't login to my Comcast Account on my PC, and none of the phone apps worked, I thought again that it might be a Cloudflare issue. But then changing DNS to others did not fix the problem. Then I tought "I'll reboot my modem just to see what happens" and just by doing that fixed the login issue. That has never happened before, and I'm not sure why the problem happened, or why rebooting my owned CM600 modem would of fixed it.