truerock2's profile

Contributor

 • 

225 Messages

Tuesday, November 23rd, 2021 10:31 PM

Closed

Xfinity is blocking Motorola MB8600 modem administrator/diagnostics screen

I have a Motorola MB8600 modem.  I cannot access the administrator/diagnostics screen at 192.168.100.1:80 because Xfinity blocks that port when it connects to Xfinity for the first time.

Is there a way to stop Xfinity from blocking port 80 on my modem?

By the way, Xfinity is not blocking port 8080 which displays a "Spectrum Analyzer".

I can do a factory-reset that allows me to get to port 80 - but as soon as Xfinity connects to the modem again for the first time, Xfinity blocks port 80 again.

Expert

 • 

110.1K Messages

3 years ago

What happens if you leave off the ":80" ?

Contributor

 • 

225 Messages

@EG

Well, leaving off :80 just defaults to :80.  It's the same thing

I've tried it both ways.

Regardless, I ran a port scanner.  Port 80 is blocked 

Retired Employee

 • 

1.4K Messages

3 years ago

Blocked Internet Ports List is a great place to find what ports we block and why. Are you able to access your admin portal without ":80"?

(Edited: Fixed Hyperlink)

(edited)

Expert

 • 

110.1K Messages

@XfinityTony

Darn echoes......... 😜 

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

Contributor

 • 

225 Messages

@XfinityTony

We would expect specifying :80 or just letting it default to :80 would do the same thing.

I've tried it both ways.

I ran a port scanner.  :80 is definitely blocked 

Contributor

 • 

225 Messages

@XfinityTony

Great link

Thanks

That web page doesn't say port 80 is blocked 

Expert

 • 

110.1K Messages

3 years ago

@truerock2 

Try hard resetting the device to factory defaults by pressing and holding in the recessed reset button on the rear for 30 seconds. This can sometimes clear up some weird behavior issues.

Contributor

 • 

225 Messages

@EG

I tried that twice.  Performing a factory reset on the modem unblocks port 80 - but, then the first time the modem connects to Xfinity, Xfinity blocks port 80 again 

Expert

 • 

110.1K Messages

I overlooked that you wrote that, sorry. Hmmm..... It's a straight cable modem / layer 2 bridge. Not a router. It has no built-in port blocking function unless they are blocking it in the configuration file or the firmware load for some reason. I don't know what else to tell you..... All I know is that people access the UI pages and post the signal stats that I request here quite often with that model modem.

(edited)

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

Contributor

 • 

225 Messages

3 years ago

Often, it is recommended that a modem be factory-reset if its port 80 is inaccessible through a router.

Last night, I disconnected the Xfinity coax cable from my Motorola MB8600 modem and performed a factory reset on the modem.  Port 80 (http) and port 443 (https) continued to be "filtered".  Port 8080 (httpd Apache based Mongoose web server used to provide a spectrum analyzer) disappeared.  I could attach my PC directly to the modem (bypassing the router) and port 80 would magically not be filtered.

This morning I re-scanned the ports on my modem (I'm using Nmap Zenmap) from my Windows 10 PC through my router and unfiltered port 8080 has magically reappeared.  I can access port 8080 on my modem through my router (a Linksys EA8500 AC2600).  Ports 80 and 443 are still "filtered".

Thousands of people frequently discuss this problem.  No one knows why it occurs.  I assume someone at Motorola and/or Comcast knows what is going on - but, the information is not available.

Where the Spectrum Analyzer app on the Mongoose web server is coming from is very strange.

(edited)

Contributor

 • 

225 Messages

3 years ago

The "spectrum analyzer" on port 8080:

Contributor

 • 

225 Messages

3 years ago

Nmap Zenmap - ports scan

Contributor

 • 

225 Messages

3 years ago

Nmap Zenmap - topology

Visitor

 • 

4 Messages

3 years ago

I am a longtime Comcast customer and IT pro who is having the same issue with my MB8600. Port 80 is inaccessible, port 8080 is open.

It is ludicrous that Comcast/xfinity essentially nerfs the modem on connection. This is anticompetitive. 

Official Employee

 • 

1.5K Messages

Good morning @tarn0ld. Thanks for reaching out to us regarding the inaccessible port, we appreciate your continued loyalty and being part of the Xfinity family. Are you able to reference the link my peer posted on the top to this thread to review the blocked internet ports list? 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

Contributor

 • 

225 Messages

XfinityGabby,

"The link my (XfinityGabby's) peer posted at the top of the thread" 

https://www.xfinity.com/support/articles/list-of-blocked-ports

Doesn't provide any useful information.  It looks like something you might set up on any firewall.

The list of articles at

https://www.xfinity.com/support/internet#get-started

Mostly stays away from the subject of modems and tends to confusingly blur when it is discussing modems and when it is discussing routers and when it is discussing gateways.

Previously to the problem being discussed here, modems would typically be running a flavor of Unix and had a web server running on them to provide a customer interface.  Usually, a lot of detailed information regarding the status of the ISP's network was provided and a log of network statistics.   All of that is running on my modem apparently - but, it is not available .

At this particular moment, http://192.168.100.1:8080/ does not respond and ports 80 and 443 are filtered.   Oh, well...

Visitor

 • 

4 Messages

@XfinityGabby​ The blocked ports list has nothing to do with this.

Comcast / Xfinity, I SEE YOU, I WILL REPORT THIS TO THE FCC

Expert

 • 

110.1K Messages

3 years ago

Wonder how the original poster is making out ?

Contributor

 • 

225 Messages

@EG​ :

I gave up.  It is obvious that Xfinity modifies the modem the first time it connects to Xfinity.

You can re-set the modem to factory setting and access it as a normal modem - but, the first time it connects to Xfinity it is modified by Xfinity and you cannot access it.

I contacted Motorola - but, they were obviously avoiding answering any question and I guess I couldn't really expect for Motorola to explain to me why and how Xfinity modifies the modem.

It is a bazar situation.  I assume it's some Xfinity techies in the sub-basement of an Xfinity office doing things that others in Xfinity have no knowledge of.  It seems to be undocumented and unknown by anyone you might talk to who works at Xfinity.  Maybe I'll run into someone at Xfinity at a social function or industry conference or something and maybe talk them into doing a little investigation into this secret situation.

Expert

 • 

110.1K Messages

Sorry to hear that man.... 🙁 Good luck !

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick
I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

Visitor

 • 

4 Messages

3 years ago

@EG Just bumping this thread and adding that even when DNS is changed at the router level, packets are making through to my computer that insert the comcast DNS VIA A LOCALHOST LOOP. 

This is literally using a vulnerability in the routing tables to track internet usage.

I look forward to sending this thread to the FCC

forum icon

New to the Community?

Start Here