We've been experiencing a very specific issue for almost a year, and it's finally becoming problematic for us. All Android devices running v5 (Lollipop) and newer are unable to view internal web sites. Browsing the public internet has no issue.
Digging further, we determined that the Androids are not able to resolve internal names. Further, a sniffer shows that the Android phones are ignoring the DNS server entries in the DHCP settings, and instead use Google's public DNS (18.104.22.168) for all name resolution--hence, no ability to resolve internal names.
We've confirmed that the devices are receiving the correct DHCP entries for DNS, the phones just aren't using it.
We have a Windows Server 2012 network, single-domain, with three sites (subnets) and four DC's, all of which are our DNS hosts. Our wireless access points are Dell PowerConnect-W model AP-105 (by Aruba Networks).
I've found internet information that seems to indicate that this might be related to IPv6 issues between Android v5(+) and IPv4 DNS:
I've focused on this because our network has had IPv6 entirely disabled (against Microsoft Best Practices recommendations) via Group Policy. If we need to re-enable/implement IPv6, that will be a challenge in the existing environment.
Can anyone provide insight on what may be the underlying issue(s) here, and how we might address it?
Please let me know if there's any further information I can provide.