Comcast CGM433 Modem & Bridge Mode - SOLVED

[Barryng]

Three years ago I switched from AT&T Uverse to Comcast due to my HOA paying for Comcast no matter if I used it and saving over $200/month. For the most part, everything wireless seems to work mostly OK with Comcast but WiFi connected devices periodically spontaneously lose their WiFi connection and then later reconnect again on their own. Today I noticed the Comcast gateway (CGM433) uses exactly the same network ID for both the 2.4 and 5 Ghz bands and, although I can get into the setup dialog, it does not allow me to change the network names. This came to my attention whentech support for an electronic door lock told me today the door lock, only 2.4 Ghz, was getting confused somehow by the Comcast Modem and its 5 GHZ signal with the same network name as the 2.4 Ghz signal.

I have a TP-Link AC5400 Tri-Band router I bought 4 years ago and never used. It seems easy to change the Comcast CGM433 to bridge mode and I found it will let me do that. So, is switching to bridge mode and connecting the router to one of the four Comcast CGM433 Ethernet ports all that is necessary? I understand I have to get into the TP-Link setup and establish network names/passwords/etc. and switch all Ethernet cables to the TP-Link Ethernet ports but is that all there is to it? I remember reading in the past that is other network parameters that must change so I am a bit skeptical about how straightforward this will be.

My expectation the TP-Link router will provide a much better WiFi signal in my house and I will suffer no loss of speed on the hard wired Ethernet connected devices. Is this probably the case?

 

[Janus67]

I believe that is correct

 

[MisterEd]

These are two of Comcast's gateways:
xFi Advanced Gateway (XB7) (Model Numbers: CGM4331COM, TG4482A)
xFi Advanced Gateway (XB8) (Model Number: CGM4981COM)

Do you have the XB7? I have the XB8.

Comcast apparently thinks we are not smart enough to maintain our own gateways. They have locked almost all the settings that you can view from your PC browser at 10.0.0.1. I have complained to Comcast technical support but they will not change their stance.

However, you can make some changes using the Xfinity app on your phone. You can change from a combined SSID to a split one and change your Wi-Fi passwords.

 

[Barryng]

Thanks. I appreciate the advice. Changing the SSIDs is exactly what I started out to do as I assumed it would be effective and easy to implement. That immediately changed when I saw I needed to load a Comcast app so I started to think about something I previously thought of doing (using my own router) but never did because it then came under the category of fixing something that was not really broken. But, it is now broken so I am thinking of doing it. I think (but am not sure) the TP-Link router, albeit 4 years old, would provide much better wireless coverage and play much nicer with all my connected devices in the house - I would certainly appreciate others thoughts on this. Also, and maybe most important, it would have been easy enough for Comcast to allow me to change the SSID directly on the router. Now Comcast requires a phone App to do that same simple thing. This absolutely makes me believe Comcast is using their App for something I will not be aware of and do not want on my phone.

 

[EarthDog]

TP-Link router, albeit 4 years old, would provide much better wireless coverage and play much nicer with all my connected devices in the house - I would certainly appreciate others thoughts on this.

Tough for anyone to say, really. Perhaps a new(er) modem/router/Wi-Fi combo would work better for Wi-Fi coverage? Not sure. You definitely have more flexibility using your own router, though.

I'd test it and see...get a Wi-Fi analyzer app and test the signal strength.... plig in your router and test that signal (you can run two different Wi-Fi.... just connect to each and test).

 

[Barryng]

I made the conversion - placed the Comcast CGM433 in bridge mode (easily done) and connected the TP-Link AC5400. To my very pleasant surprise, the Ethernet connection, through the Comcast CGM433 in Bridge mode but via the TP_Link switch, is very noticeably much faster. I did no benchmarks but my PC accesses and displays sites with an immediately obvious much more snappy response than previously and the three TVs/Comcast STBs, all connected via Ethernet, are also noticeably faster to respond. The WiFi signal appears more consistently strong throughout my home.

HOWEVER, I cannot access the TP-Link setup dialog; a necessary task to change the TP-Link default SSIDs and Password. Entering 192.168.0.1 or tplinkwifinet (with or without the http:// prefix) consistently produces an "Unsupported Browser ..." error message. I tried Firefox, Edge (even in IE mode), Chrome, an iPhone (using the default wireless SSID/password), a late model iPad, and a Samsung Android pad, all with the same results. TP-Link tech support had me reset the C5400 etc. and nothing worked. At that point TP-Link told me, politely, of course, I was SOL as this router, although in an opened box for the past 4 years, is beyond the two year support period. Not being able to secure the WiFi system from the factory default means I cannot use it. I Googled the problem and found this issue is very widespread. Although a ton of questions popped up, noone appears to have found a solution that consistently works. I am now giving up on it for the night, will try again tomorrow, and if not successful will just toss it and go back to using the Comcast CGM433. This will be painful because the much faster internet speeds is an addiction that will now be hard to break.

TP-Link tech support did, as a last ditch effort, want me to load their "Tether" software on my iPhone but this required establishing a username/passsword account with TP-Link so I refused to go down that rabbit hole.

In all respects this TP-Link C5400 appears to be a great router in all respects except the no-go issue of not being able to access the setup dialogs. The Google responses are numerous, pertain to other TP-Link models, go back a lot of years, and some have reported this issue started with a firmware upgrade. So, I find it just inconceviable that TP-Link has done nothing about it although that is obviously the case. Maybe the problem ws an inadvertent bug in a firmware upgrade released to manufacturing and not being able to get into the setup dialog means there is no way to replace the buggy firmware.

 

[Barryng]

OK! Success!

In another forum someone suggested using Portable Firefox. I never hear of this so I did a bit of research and then felt somewhat comfortable to download a portable version from Pale Moon. I used Pale Moon because they gave a short list of specific instructions that nailed the questions I had about how to use it. I installed it to a USB drive and to my truly great surprise the thing worked from the USB drive and I was able to open the TP-Link setup dialog!

After making the setting changes I checked the firmware and to no surprise there was a later version. I was very reticent to install the latest firmware because of all the comments I saw about this problem appearing after a firmware upgrade. I debated and decided to take a chance and installed the new firmware. After the installation completed it tried to restart the setup dialog using http://tplinkwifi.net and the setup dialog would not open. I then manually tried 192.168.0.1, as I used initially, and, to my relief and surprise, there was no problem.

BTW, after loading the new firmware, again without any benchmarks, internet speed seems to have slowed but just perceptibly so, although it is still faster than prior to placing the Comcast box in Bridge mode.

Thanks again. It was really pissing me off to have spent so much for this thing, even though that was four years ago (it was still in the shrink wrap yesterday), and not be able to use it so I certainly appreciate all the thoughts provided above. Thanks!!

UPDATE: I just discovered, probably due to the firmware upgrade, I can now enter the TP-Link setup dialog using Firefox from my Ethernet connected PC.