Hitron CGN3 in bridge mode broadcasting wifi

[Eli_Sand]

I have my CGN3 in bridged mode and I noticed that it is broadcasting a wifi signal.  The wifi it's broadcasting isn't a hidden network, but in fact (more annoyingly) the last configured wifi network name I had set up.  That same wifi SSID is now being used by an access point I have in my house - so the Hitron is now showing up as a potential security threat (looks like an AP trying to get my clients to connect to it instead and sniff out passwords or something).  Obviously when the CGN3 is in bridged mode, it should disable wifi completely; I shouldn't see any power going to those antennas.

I know this has been an ongoing issue for years now and I believe is also related to a very similar issue with regards to a hidden network broadcast from the router when not in bridged mode.  From searching forums, it seems these issues have been reported and that Hitron and Rogers are aware of them, yet years go by and no fix?

Why is this still unfixed, or is there a new firmware that maybe hasn't been pushed to my device that fixes this problem?  If it's not fixed, why not?  If the fix is planned, why has it taken years without any action?

I even made a little cardboard "box" of sorts that sits overtop of it and has some thick tinfoil on both sides and drapes over both sides to block the antennas - however even that isn't enough that my access point can detect a very faint -87db signal and happens to be on the same channel as my current wifi; so causing interference.

Short of cracking open the CGN3 and physically disconnecting the antennas, how can this be fixed?

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[Datalink]

I've been a Rogers modem user long before the introduction of the original CGN3 modem, and I can say that cases where a user has reported wifi networks broadcasting from a bridged modem have been few and far between.  I can't remember any case off the top of my head where the modem was actually found to be operating in Bridge mode and broadcasting a wifi network.  Usually the report is raised by a new user who has attempted to set the modem into Bridge mode and has been unsuccessful for some reason.  The end result, the modem continued to operate in Gateway mode with the wifi networks in operation.


Ok, so what would I do if faced with this possibility?  I would set up inSSIDer to monitor the wifi network, then I would disable the access point and watch the access point wifi networks drop in power level and disappear off of the display after about 4 to 5 minutes.  If the modem, in Bridge mode is transmitting one or both networks, then those networks should be visible on the inSSIDer display.  Then I would pull the power from the modem and see if in fact that those networks disappear.  If not, then someone else is using the same SSID(s) for some reason possibly in an attempt to spoof your network(s).

If the networks did in fact drop from the inSSIDer display, power up the modem and log into it using 192.168.100.1 and check for the following:  Status, Basic, Wireless, Admin, Security, Advanced tabs at the top of the page.  If those titles are there, the modem isn't operating in Bridge mode.  If those tabs are not all there, you should only see the Status, Basic and Admin tabs when the modem is in Bridge mode.  If thats the case I would run a factory reset.  Then, after the reset and reboot, I would completely fill in the wifi SSIDs and passphrases with random characters, turn off WPS and set both networks to WPA-2 and AES only.  Do not use TKIP as it is no longer secure, same as WPS.  I would also set the channel to some channel that is really busy so that it couldn't interfer with your access point in the event that it ever was transmitting, which it shouldn't.  When that is done, I would then disable both wifi networks, taking note of the first few characters of both SSIDs.  

While doing this I would have a laptop setup to run inSSIDer, monitoring the wifi networks.  When the networks are disabled, it will take about 4 to 5 minutes for those networks power levels to drop and followed by the networks disappearing from the inSSIDer display.  That should prove that the networks are actually disabled and not transmitting.  The only thing that should be left are networks from your neighbour's modems and routers, including anyone attempting to spoof your network or, someone who just happens to be using the same SSID.  

http://www.techspot.com/downloads/5936-inssider.html

Then I would kick the modem into Bridge mode:  navigate to BASIC .... GATEWAY FUNCTION, and disable the Residential Gateway Function.  Save the setting and watch the modem reboot into Bridge mode.  I would keep watching inSSIDer for any sign of the wifi networks that you set up using random characters for the SSID.  

When the modem is operating in Bridge mode, there should be no sign of the wifi networks that you had setup using the random character SSIDs and passphrases.

As for the cardboard box that you have constructed, if you have one of the CGN3xxx series modems, ie, a black rectangular shaped modem, then the cardboard box will do no good as the wifi antenna are mounted on one side of the motherboad which sits vertically in the modem case, which should be standing upright.  You wouldn't be able to cover the antenna without entirely covering the modem and you would end up cooking the modem.  As it is right now, if it is a CGN3 series modem, with the top covered, the only thing that is saving you at the moment from cooking the modem is that there are ventilation passages within the sides of the modem case.  If you have a CODA-4582 which is a white modem, then placing a cap on the modem to cover the antenna, which are located at the top in this modem, will probably end with the same result, cooking the modem.  So, thats not a great solution.  

Wrt to the hidden SSID networks, there is a Rogers product that runs a secondary network, so there is a legitimate reason for it to exist.  At some point in time this should be taken care of for those modem that don't necessarily need that network, but, I don't have any timeline for that to happen.  

If after all of this, you have proven that the modem is in fact transmitting wifi networks when its in Bridge mode, swap the modem.  Put a note on it with a brief explanation:  Modem transmitting wifi while operating in Bridge mode.

If you have reason to think that someone is spoofing your network, then you should change your SSIDs and Passphrases, and use the entire field length available for both. 

[Eli_Sand · Accepted solution]

I have in the past confirmed quite certainly that these modems can and will broadcast a wifi beacon sometimes when in bridged mode.  I even came across the release notes for the firmware and noted in there was this specific issue.  I don't know if it's been fixed in new firmware since that time, but I do know it's a real issue and I've experienced it myself before.

Anyhow, I reset the modem to factory default to rule out the issue and it turns out that it is in fact a far-away neighbour that only my commercial access point can pick up from my location, but not my other wifi devices.

As for the tinfoil box - I am aware of the passive cooling the modem uses and it's not a complete box, more of two flaps covering the sides with the antennas and I've made sure it doesn't interfere too much with airflow (it doesn't, however I have not tested how efficient it is at blocking a wifi signal either).