IPv4 not working on Ignite CGM4331COM router

[heihei]

I recently got new ignite router installed, and I used pod to replace my previous wifi mesh network. Everything seems fine. But this morning, my 2 pcs have some networking issues, and I found they don't have ipv4 addresses assigned.

ifconfig doesn't show IPv4 addresses.

The 2 linux PCs are connected to a pod. I power cycled the pod, but that didn't fix it. Then I went to the network settings and manually assigned static IP addresses for the 2 PCs, and everything works.

I guess the DHCP on the router is in a bad state. Power cycling the router might also work, but that would break everyone's internet connection.

Also I have never experienced such a issue with my previous router. That should mean it is not a problem of my PCs.

I think it is a bug of the router's firmware, and hope they can fix it in next update.

PS: IPv6 was working well. I could still use some websites (not all). Also my router is configured to allocate dynamic IPs in a range, and some devices are assigned static IP addresses. That shouldn't be an issue though. The ignite app said that my PCs were assigned some IP addresses. I am feeling it may be something to do with the IP lease time. I previoulsy set it "never", but it is 2 days now (it may have been modified by Rogers technician). So 2 days ago may be the time my PCs got the previous dynamic IP addresses assigned.

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[-G-]

@heihei  I experienced a similar problem with my XB6 gateway where I saw partially broken IPv4 connectivity.  (I normally run with the XB6 in Bridge mode and use my own router but I was doing some tests in Gateway mode (with no external router) at the time.)  I think that IPv4 was actually healthy from a routing/networking-layer perspective but DNS lookups over IPv4 (querying the XB6) were failing.

My IPv6 connectivity remained completely healthy.

The "Test your connection" button on https://en.internet.nl confirmed what was/was not working, at least from my computer's perspective.

I rebooted my XB6 and everything went back to normal again.

I reported this problem to Rogers but until now, had never seen anybody else report IPv4 brokenness in the Forum.  I initially wondered my XB6 was defective, and I reverted back to Bridge Mode and using my own router.

[heihei]

@-G-In my case, once I configured PCs to use static IP (and set DNS server to be 10.0.0.1), the problems are gone. It is more like DHCP for me (ifconfig on ubuntu didn't show any IPv4 address for the ethernet interface). I just increased the router's DHCP range from 2-100 to 2-200 and hope that will help.

Thanks for the link https://en.internet.nl . I will try it next time I see the problem

[-G-]

@heihei  In my case, I could not connect to www.imdb.com but could connect to http://10.0.0.1 and could ping 8.8.8.8 , so IPv4 definitely was still working and the devices on my local network still had IPv4 addresses and active DHCP leases.  The DNS lookups were failing and that caused applications to break.  Anything that used IPv6 still worked fine.

[heihei]

@-G-I couldn't ping 10.0.0.1 when the problem happened.

[-G-]

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@heihei wrote:

@-G-I couldn't ping 10.0.0.1 when the problem happened.

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I would guess that in both our cases, some aspect of the IPv4 DNS/DHCP services on the Ignite gateway either partially broke or died for whatever reason.  In my case, my DHCP leases apparently had not expired yet.  In your case, they did and you could not renew, and as a result had lost a lot more IPv4 connectivity.

I'm still not entirely sure about my guess because apparently you could still get DNS replies from your XB7.  I also think that at least one of my systems or browsers would have been resolving through a 3rd-party DNS service, and I do not know what would have been blocking or breaking that connectivity.  (Sorry.  This happened a number of weeks ago and I can't quite recall all of the details.)

Your XB7 and my XB6 gateway are both made by Technicolor and would share common code.  Regardless of what broke, I still suspect that our problems stem from the same root cause.  Unfortunately, I did not see anything in the XB6's logs that indicated any problem of any kind, and we don't have any ability to troubleshoot problems with the inner workings of the Ignite gateways.

[-G-]

@heihei  Found this thread on the Xfinity support forum: https://forums.xfinity.com/conversations/your-home-network/xb7-gateway-connection-issues/602daf22c53...

It sure looks like the original post could be your problem.

I don't know why the accepted solution was to disable the xfinitywifi public hotspot.  Rogers does not support this functionality (yet?) so this is not something that we can even try to improve stability.