Why is my Default Gateway not

mberry47mberry47 Posts: 2
edited August 21 in Internet 2019 Archive Jan 19, 2019

Recently, and randomly, the default gateway on my Arris modem changed from to fe80::201:5cff:fe75:5e46%7.  At the same time, the switch that i have connected to my modem stopped working correctly - It will only allow 4 ports to be active at any time (i am using 8 of the 16 ports for various LAN connections, google wifi, and ooma telo).  I have spoken to Spectrum 3 or 4 times, and one of those time the technician was able to do a factory reset that changed the default gateway back to and the switched worked again.  Then a few days later, the gateway went back to the nonsense letters and the switch went back to only 4 ports working.   They have no idea why it's happening.  I should mention it's an unmanaged gigabit switch.  Anyone out there know what's going on?  Thanks!


  • mberry47mberry47 Posts: 2
    Jan 19, 2019

    i should also add that i cannot get into the modem interface when the default gateway is not, so i'm unable to look at any of the settings in the modem.  And the modem is one supplied by Spectrum, not one i purchased.

  • RAIST5150RAIST5150 Posts: 835 ✭✭✭✭
    Jan 19, 2019
    IPv6 address versus IPv4 addressing. Have you tried yet?

    If that doesn'twork either, and you are using a router you can try disabling IPv6 there, making everything v4 on your side. Then you should be able to hit it via something like,, and such.

    Alternatively, you could try disabling IPv6 in the client's tcp/IP properties.
  • Smith6612Smith6612 Posts: 44
    Jan 20, 2019

    Personally, I would avoid disabling IPv6 anywhere, and certainly wouldn't disable IPv4 Smiley Wink


    OP, try,, or If none of those work, run "ipconfig /all" on your machine, and look for your Default Gateway that isn't listed as the IPv6 Default Gateway. If the router's pages won't load, reboot the router. Some of the Askey / Sagemcom routers Spectrum provides have a tendency to have the web interface crash even while the router is still working.


    Keep in mind, if you have a computer connected directly to the cable modem, and your modem is an E31H2V1, H31N2V1, H31T2V1, or an H31U2V1, those typically don't load their web interfaces at any IP address. THe H31U2V1 is the only one that has been gotten into, with some tricks. These are modems only and there is nothing to configure in these.

  • karlbeckmankarlbeckman Posts: 2,228 ✭✭✭✭
    Jan 21, 2019

    It's true that there are no configuration options in those modem-onlys, but the user should still have read-only access to the signal level/channel assignment and error/status report pages.  Sadly, Spectrum has been disabling access to those pages, which makes almost impossible for the user to perform even the most basic troubleshooting and network problem analysis when their speeds drop off or something else fails. 

    There's nothing inherently wrong with disabling IPv6 in the LAN router.  How many subscribers have connected devices that are IPv6 only with NO IPv4 compatibility?  That's the only time they must have IPv6 running on their home LAN. In fact, disabling IPv6 on the internet router is necessary when the customer has the TM1602 eMTA modem, used for combined VoIP telephone plus internet service. 

    Lasst, for @mberry47 , next time tell us what IP addresses your computer's assigned IP and the default gateway changed to.  That tells a lot about what is going on with your router and home LAN.

  • RAIST5150RAIST5150 Posts: 835 ✭✭✭✭
    Jan 21, 2019

    @Smith6612 wrote:

    Personally, I would avoid disabling IPv6 anywhere, and certainly wouldn't disable IPv4 Smiley Wink



    Was a typo... edited the post.


    Disabling v6 on the LAN side shouldn't cause issues here. May even address problems with some online games in fact, especially if multiple clients are trying to play together at the same time. More commonly an issue with consoles, but can still cause weirdness in the PC realm here and there.

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