2025-08-22T19:21:05+00:00 Laminas_Feed_Writer https://noahvanbochove.nl/ 2025-07-18T00:00:00+00:00 2025-07-18T00:00:00+00:00 https://noahvanbochove.nl/article/ipv6-issues-on-phones-when-using-unifi-aps Noah van Bochove mail@noahlvb.nl https://noahvanbochove.nl/ Recently I have been experimenting with IPv6 because I recognized it to be the future for the internet. I install and maintain a handful of small business networks and I wanted to get experience on IPv6 before deploying it commercially. So I decided to make my home network IPv6 first / mostly and my servers IPv6 only when possible. After some learning I found IPv6 way more intuitive then v4 but struggled with the mobile devices on Unifi AP's. So I though I share a bit on that to help others out deploying IPv6 networks. Proxy ARP At first I was unable to get IPv6 to work reliably or at all over wifi, it turned out that Unifi AP's often times have proxy ARP enabled. Normally this is desirable on wireless networks since it reduces a lot of broadcast traffic which can degrade larger wireless networks. But it turns out this proxy ARP setting not only proxies ARP traffic but also ICMPv6 traffic. The way the traffic is proxied breaks IPv6 ND which is the method of auto configurating IPv6 on Apple and Android phones. Expiring Router Advertisements do to DTIM setting Disabling proxy ARP was not the whole story, I though I had success since IPv6 worked on all my wireless devices in the house. After some time my Google Pixel 7 pro no longer had IPv6 connectivity. Interestingly my wife her Pixel 7 (non pro) had no problems. Some searching on the internet and tinkering around I discovered that this issues only happens when my phone was not used a lot (read screen off time). It turned out that the IPv6 Router Advertisements (RA) were expiring before the phone received a new RA. I first tried making the lifetime of the RA's longer, but even a lifetime of 24 hours was not long enough, some times the phone would still miss the RA's. This told me that even after increasing the RA's lifetime the chance of my phone missing a RA would still exist. After stumbling upon a thread on Google's public issues tracker I learned that tweaking the DTIM setting on the AP's could take away the mismatch in AP sending and phone sleeping behavior making sure no relevant broadcast traffic is missed by the phone. Apple recommends a DTIM setting of at least 3 and my pixel 7 pro required it to be set to 5. It has to do with the way different vendors implement wifi on their devices, devices can have varying DTIM multipliers that together with the AP's DTIM setting effect wifi sleeping behavior. I was hesitant at first because I feared battery life on my wireless devices would suffer but I have not experienced any negative effects. Multicast Enhancement There is also a setting called Multicast Enhancement on Unifi AP's. This function converts multicast traffic into unicast traffic, again to improve wireless performance. I have been able to run IPv6 over wireless with this option enabled but connecting to the network takes way longer for some reason, so I have it disabled on my networks. Your mileage may vary. Learning IPv6 in practice This little side quest to setup IPv6 told me that so many things I know about IPv4 just do not translate to IPv6. I hope this writing may be useful to someone experiencing similar issues on their network. While IPv6 on paper is quite simple, in practice there a many little quirks or vendor specific nuances that are good to know and share.