There was a common problem in the past where the modem MAC address would be entered incorrectly during activation and that would break IPv4. That hasn't been a problem since last November since our engineers found a way to detect when this occurred and fix it automatically.
Since that time, many have reached out for help with general IPv4 issues, but the root cause is almost always on the user's side. A very common culprit is Wifi extenders, extra routers, or some other network device (like an Apple Airport Extreme) that is acting as a DHCP server and handing out IPv4 addresses. In cases like that, a home device can get the wrong IPv4 addressing information, which breaks IPv4 connectivity to the internet.
Another common, related issue is when you change what is physically connected to the modem. Any time you do that, you *must* reboot the modem for DHCP to work properly.
Less common culprits are parental controls and web filtering. I even saw a case where someone accidentally enabled time-based parental controls, so their internet would stop working at the same time every day and they didn't know why. If you have your own router, sometimes it's fastest to reset the router to factory defaults and start over rather than troubleshoot existing settings.
Occasionally, I see cases where people have disabled DHCP on their network interface card and have given themselves a static IPv4 address, and then forgot about it. It's always helpful to verify that your NIC is set to obtain IPv4 addresses automatically.
Does any of that help?
Web searches regarding this issue lead me to believe my MAC address needed fixing, I suppose according to most commonly opened links, as Google saw them. I wish their system was smart enough to sort by date and relevant content. (i.e., last year's issue was fixed in November!)
The above reply helped me decide to reset everything and find that I'd previously been routing through incompatible addresses. Problem is solved and I wish I could mark the above as best answer! Thanks John!
We have a Comcast business Dual Band WiFi BWG router/modem combination.
If you are a Business Class subscriber, please post your concern here;
This forum is for residential customers.
Could you share some of the steps you would take to fix user error that would prevent IPv4 from working on a device? I'm connected fine from another laptop without issue but my Aspire E 15 can only connect with IPv6, like others on the forums have been saying ... this leads me to believe its a connection issue with the device rather than something to do with the modem or any additional hardware (which I don't have anyway). Furthermore, this on appears to happen when I'm connected to my newly installed home wifi ... it works fine on public wifi like at a coffee shop. IPv4 and IPv6 are both set to "obtain an IP address automatically," i've tried rebooting modem. What else can I do to find out the cause on my end? Many thanks in advance.