Win32::Resolv.get_resolv_info returns unavailable DNS servers
Win32::Resolv.get_resolv_info returns a list of IP address that include DNS server for network devices that are not connected, causing long timeouts when using
Resolv::DNS (or Rubygems which uses
Win32::Resolv scans the registry for DNS server addresses. Unfortunatly, if some of your network devices are not currently connected, the old DNS information is still stored in registry. So
get_resolv_info still returns it. This can cause very long timeouts when using
Resolv::DNS (e.g. rubygems). For example, a simple 'gem install' on my machine would take over a minute, because of several timeouts waiting for DNS.
irb(main):024:0> Win32::Resolv.get_resolv_info => [["mynet", "mycompany.local", "local"], ["192.168.1.1", "172.27.0.1", "188.8.131.52", "184.108.40.206", "192.168.101.10", "192.168.101.11"]]
- 192.168.1.1 is the DNS server from my home Wifi (not currently connected)
- 172.27.0.1 is the DNS server from a router I had connected via an USB Ethernet Device a week ago
- 220.127.116.11 is from the same as above (but incidentally works, since it is available)
- 192.168.101.10+11 are the actual current DNS server
I think a solution could be to rely on
GetAdapterAddresses() in the Win32 API instead to get the IP address of DNS server.
As a workaround for users affected by this is to remove unconnected Interfaces from
HKLM\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces in the registry.