P8P getting IPv6 but no IPv4 lease on home network?

Ziladus

Hey guys,

Having a really weird network issue with my Pixel 8 Pro on the latest GOS (Android 17). Basically, on my home wifi, my phone connects and gets an IPv6 address instantly, but it absolutely refuses to get an IPv4 address. Mobile data works fine, but on wifi, anything that is IPv4-only is just broken. My friend who I got to switch to GOS is actually having the exact same issue.

I ended up pulling some ADB logs to see what was going on under the hood.

When I toggle the wifi, the phone connects (supplicant state says completed), but wlan0 just sits there with no IPv4. It broadcasts DHCP discovers for about 15 seconds, but it never gets a DHCPOFFER or ACK back. IPv6 literal and DNS probes work perfectly with 0% loss.

I tested a standard Android 15 phone on the exact same network. It connects instantly and the router gives it a 10-day DHCP lease.

I'm 99% sure this is related to the aggressive per-connection MAC randomization. My guess is that because the MAC changes every single time I reconnect, it's just filling up the router's DHCP table with stale leases until the router refuses to hand out new ones. The control phone uses standard randomization, so it doesn't trigger this.

Is this a known issue with aggressive MAC randomization on certain routers? Do you guys just disable the per-connection randomization for your home networks, or is there another workaround I'm missing?

(Btw, English isn't my native language, so I hope the technical details make sense!)

Cellobright

Ziladus Have you tried disabling per-connection or per-network randomized MAC address and confirming it works before speculating that the "aggressive MAC randomization," which most devices now practice, including on some Android flagships made by Chinese manufacturers, enable by default as per-network randomization?

de0u

Ziladus This is a frequent issue with consumer-grade routers. Switching to per-network and rebooting the router is a good test.

Ziladus

Cellobright I tried disabling it and restarting the phone, but the result was the same. Interestingly, the issue seemed to be resolved for a while (about 14 hours) even with MAC randomization turned on. However, the problem has now returned with the exact same symptoms.

Cellobright

Ziladus One potential solution from FAQ for routers that do not accept new clients:

In rare cases, broken routers are unable to accept new clients once their DHCP table is full instead of clearing the last recently used entry. You can work around this by manually clearing the DHCP table via the router administration page and can switch to the per-network randomized MAC mode to avoid triggering the issue again. This would prevent a router being used in any situation where many clients naturally come and go even without per-connection MAC randomization and is not generally an issue for any modern routers. Per-connection MAC randomization only makes it more likely to find a one of the rare routers with this issue.

GrapheneOS does not deviate from AOSP Wi-Fi behavior apart from allowing you to randomize your MAC address every connection to it (as opposed to a unique but persistent MAC address). Can you try doing what the FAQ suggested?

In addition can you press on the cog next to the Wi-Fi you connect to and check if the "Security" (should be WPA/WPA2-ersonal or WPA3-Personal; WEP is outdated but still in use) "Type" (shows Wi-Fi version) and if "Gateway" show anything interesting?

posting2340

I would check your routers admin page and see what IPs are being assigned to your wan interface to first see if the issue is network wide or isolated to your device. Though the probability of your ISP only assigning you IPV6 seems pretty unlikely.

0xC0DED0D0

posting2340 Though the probability of your ISP only assigning you IPV6 seems pretty unlikely.

No ISP could currently operate their business this way, that is correct.

But the effect of not using NAT in the home network would be the same. Blow through all available IPv4 leases (usually not more than 2-5 per subscription – only ONE is really needed anyway), yet have effectively unlimited IPv6 addresses (/56 subnet).

So, if OPs experience is that only a few devices get IPv4 addresses, yet ALL devices get IPv6 – a non-NATing router is the culprit. Either set to "Bridge" mode OR connected "backwards" with WAN cable connected to one of the router's LAN ports.

Both will effectively turn the router into a simple switch instead, with this issue resulting.

SplatterGames

0xC0DED0D0 a non-NATing router is the culprit.

Impressive, how would you even come to this conclusion??! This is really bad and unhelpful advice.

@Ziladus you need to find a common denominator between you and your friend. Something in your setup is breaking DHCP. Disable every VPN, set Private DNS to "off" and also try connecting via static IP instead of DHCP by cloning the WiFi settings of your working Android 14 device (although change the IP address to an available one in the subnet range to avoid conflicts).

For complete troubleshooting it would also be great to have insights on the router side, so check if there are any errors in the logs. (probably related to DHCP or DNSmasq for most consumer routers)

0xC0DED0D0

SplatterGames Impressive, how would you even come to this conclusion??!

Here's how:

posting2340 see what IPs are being assigned to your wan interface

WAN mentioned.

0xC0DED0D0 if

Also known as a qualifier.

SplatterGames This is really bad and unhelpful advice.

Thank you for your kind reply.

Ziladus

Cellobright I checked the router DHCP table and it had about 200 clients in the "unused devices" section. Clearing that worked and the problem seems to be resolved. Also, the security type is set to WPA3-Personal. Thanks for the help.

posting2340

Ziladus maybe check your router now and see what the DHCP lease length is set to. For instance, mine is at 12hours.

Ziladus

posting2340 It was set to 10 days by default. I now set it to one day which is the lowest possible, thanks for the suggestion.

Cellobright

Ziladus if this is solved then great, can a mod add the [Solved] tag please