Weird hidden network

Discussion in 'Tomato Firmware' started by ras07, May 10, 2018.

  1. ras07

    ras07 Network Guru Member

    I recently installed AdvancedTomato Version 3.5-140 on a Netgear R6300v2. Ever since, I keep seeing this open, hidden-SSID network show up (such as on Windows or Android devices). It's on the same channel as my 2.4 GHz wifi, and if I change channels, it moves with it. If I turn my router off, it goes away. So I conclude it is being generated by my router.

    I was trying to configure a VLAN, and thought it might be related to this. I deleted all the VLANs, but it was still there. I went so far as to wipe the NVRAM and reconfigure manually. As soon as I enable wireless, the hidden network shows up.

    The network shows up with no security, although since the SSID is hidden I can't connect to it.

    Any idea what's going on?
  2. Sean B.

    Sean B. LI Guru Member

    In Tools->System commands run:

    wl -i eth1 status
    This will pull information straight from the wireless driver. Example:

    root@Storage:/tmp/home/root# wl -i eth1 status
    Mode: Managed   RSSI: 0 dBm     SNR: 0 dB       noise: -92 dBm  Channel: 6
    BSSID: XX:XX:XX:XX:XX:XX        Capability: ESS ShortSlot RRM
    Supported Rates: [ 1(b) 2(b) 5.5(b) 6 9 11(b) 12 18 24 36 48 54 ]
    HT Capable:
            Chanspec: 2.4GHz channel 6 20MHz (0x1006)
            Primary channel: 6
            HT Capabilities:
            Supported MCS : [ 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 ]
    If something is active on the 2.4ghz radio, it will show there.

    **EDIT** Also, are you running 40 or 80mhz channel widths? I faintly recall having seen some devices seeing fat channel blocks like that as a main AP and a ghost AP. If you are, may be worth dropping it down to 20mhz and see if your devices still see that ghost AP, if not then it's not really a second broadcast.
  3. PetervdM

    PetervdM Network Guru Member

    do you by any chance have a chromecast device in your network? try switching it off. i had a situation like this, the hidden channel hopping in sync with the AP. eventually it was the chromecast, not the AP.
    Sean B. likes this.
  4. ras07

    ras07 Network Guru Member

    I do have a chromecast! I will investigate.
  5. ras07

    ras07 Network Guru Member

    It appears that was it! What odd behavior.

    Incidentally - every so often I see an SSID called "LG TV" pop up (always on Channel 6, as I recall). I thought it was coming from my wifi-enabled TV - except that it sometimes appeared even when the TV was unplugged. Which was kind of spooky. But of course the Chromecast has its own power supply, so I'm sure that's it. (I probably named the Chromecast "LG TV".) I hadn't noticed it before but I'm willing to bet that when the "LG TV" SSID appears, the phantom hidden network disappears, and vice versa.

    Sean B.: my results look just like yours, and I was running 20 MHz channel widths. Interestingly, if I enable virtual wireless, it does not show up in the status results - is there another command to display that?
  6. Sean B.

    Sean B. LI Guru Member

    Hmm, I thought that would show virtuals as well. Try:

    wl dump
    Note that the driver will default to the 2.4ghz interface ( eth1 ), if your router is dual band you would need to specify the 5ghz interface ( eth2 ) for any info/commands from that radio. IE:

    wl -i eth2 dump
    If that doesn't list everything, then apparently the driver segregates by interface even when using the same phy. Which means you'd have to specify the virtual AP's interface by name. IE:

    wl -i wl0.1 status
  7. ras07

    ras07 Network Guru Member

    Dump gave me both physical and virtual - thanks
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