I am looking for a way to receive a notification whenever the configured DNS server address of a network interface changes, using native Windows APIs (C/C++). For both performance and reaction time reasons, I'd obviously want to avoid polling.
There is, for example, the NotifyIpInterfaceChange API in Iphlpapi.dll. In my tests, it reliably triggers a notification when the host's IP address, subnet mask, or default gateway changes, but not at all when only the DNS addresses change.
My only "solution" up to this point is using WMI event queries, but it actually polls in the background, so to avoid hogging down the system, the polling interval (WQL WITHIN clause) needs to be set to several seconds, which results in a long and annoying delay for my application. Also, for various reasons (which are not the topic of this discussion), I prefer to avoid WMI usage anyway, resorting to it only when there is no other way.