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Forum Discussion
Why is Xfinity blocking access to the spectrum analyzers?
Copied from a reddit discussion on the unofficial Comcast page. Could not get a definite answer.
Recently discovered that port 8080 buy doing a port scan of the modems log in IP that Comcast is blocking the analyzer by http proxy.
Why are they blocking this? It wasn't enough that they told modem manufacturers to not display unerrored codewords. Now we can see the analyzers now.
There was a short window where I could access it, where I would disconnect the coax cable from the wall plate. Then allow the modem to lose connection, after that I could see it for a few seconds. Before the modem downloaded the configuration file.
There was a log in page to get to it as well.
Does Netgear use any services on port 8080 with their modems?
4 Replies
It's accessible for me on my CM3000 with Sparklight:
Port 8080 is commonly used as an alternative port for http.
Xfinity says they are NOT blocking the port.
Though that could be incorrect I guess. You can check for that with https://canyouseeme.org
That said, not all modems support the spectrum analyzer tool (which is built into the modem itself). And there was an old security vulnerability in the tool (as discussed in the reddit discussion), so they might have simply blocked the service. Best way to sort this out is to contact Xfinity support.
So they fixed the exploit and one point in time? Seeing the CM2000 is obsolete and I am just waiting for my area to get upgraded for the next generation speeds, I suspect they kept it blocked.
I did contact them directly, then was told it wasn't blocked. I assume they got confused and thought that I meant it was about me hosting a server. Not that I was talking about a tool within the modem.
Nmap shows it is there. Like I said there is a window where it can be accessed. Nmap was used by scanning the login IP for the modem.
I did contact them directly, then was told it wasn't blocked. I assume they thought that I meant it was about me hosting a server.
Likely yes.
So they fixed the exploit and one point in time?
The fix might have been to disable the service, or lock it down so it could only be accessed by Xfinity support. Of course there is no way to exploit the vulnerability when the modem isn't connected to the ISP, which could explain the short window you are seeing.
FURRYe38 might know if there is any way to reach the analyzer, as he once owned a CM2000.
Is this hypothetical, or is there a performance issue you are trying to troubleshoot?
