net: DNS requests do not work on Android

[timcooijmans]

DNS requests on Android from JNI libraries do not work: Go tries to do the DNS lookup itself by connecting to the local DNS server over UDP but nothing seems to be listening.

I/GoLog﹕ lookup google.com on [::1]:53: read udp [::1]:35142->[::1]:53: connection refused

Code used:

func LookupTest() {
    _, err := net.LookupIP("google.com")
    if err != nil {
        log.Fatal(err)
    }
}

This code is called from an Android class by the JNI wrappers provided by gomobile bind.

This issue may be related to or the same as #8877 but I'm not sure.

Android version: 5.1
Go version: devel +4ddd751
x/mobile version: master branch tip: #601608a0e07a5bd0cf7fddbfc9b7d5f6b23e9476

[gopherbot]

CL https://golang.org/cl/9793 mentions this issue.