HttpURLConnection in Android working fine, but OkHttp gives "Network is unreachable" on Kitkat

Question

I have a problem with this particular site: https://tastedive.com/read/api

If I do an HTTP request with HttpURLConnection, I get a normal HTML response (on Android this code needs to be in a separate thread and also put all the necessary tries and catches):

    StringBuilder result = new StringBuilder();
    URL url = new URL("https://tastedive.com/read/api");
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    conn.setRequestMethod("GET");
    BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
    String line;
    while ((line = rd.readLine()) != null) {
        result.append(line);
    }
    rd.close();
    System.out.println(result.toString());  // shows normal HTML response

But if I do it with OkHttp, with this code...

    OkHttpClient client = new OkHttpClient();
    Request request = new Request.Builder()
            .url("https://tastedive.com/read/api")
            .build();
    client.newCall(request).enqueue(new okhttp3.Callback() {
        @Override
        public void onFailure(okhttp3.Call call, IOException e) {
            Log.d("MY", "failure", e);
        }

        @Override
        public void onResponse(okhttp3.Call call, okhttp3.Response response) throws IOException {
            if (!response.isSuccessful()) {
                throw new IOException("Unexpected code " + response);
            } else {
                System.out.println(response.body().string());
            }
        }
    });

...I get this error in onFailure:

   java.net.ConnectException: Failed to connect to tastedive.com/2606:4700:30::681c:3a5:443
       at okhttp3.internal.connection.RealConnection.connectSocket(RealConnection.java:242)
       at okhttp3.internal.connection.RealConnection.connect(RealConnection.java:160)
       at okhttp3.internal.connection.StreamAllocation.findConnection(StreamAllocation.java:257)
       at okhttp3.internal.connection.StreamAllocation.findHealthyConnection(StreamAllocation.java:135)
       at okhttp3.internal.connection.StreamAllocation.newStream(StreamAllocation.java:114)
       at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:42)
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147)
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121)
       at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:93)
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147)
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121)
       at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93)
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147)
       at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:126)
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147)
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121)
       at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:200)
       at okhttp3.RealCall$AsyncCall.execute(RealCall.java:147)
       at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32)
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
       at java.lang.Thread.run(Thread.java:841)
    Caused by: java.net.ConnectException: failed to connect to tastedive.com/2606:4700:30::681c:3a5 (port 443) after 10000ms: isConnected failed: ENETUNREACH (Network is unreachable)
       at libcore.io.IoBridge.isConnected(IoBridge.java:223)
       at libcore.io.IoBridge.connectErrno(IoBridge.java:161)
       at libcore.io.IoBridge.connect(IoBridge.java:112)
       at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
       at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
       at java.net.Socket.connect(Socket.java:843)
       at okhttp3.internal.platform.AndroidPlatform.connectSocket(AndroidPlatform.java:71)
       at okhttp3.internal.connection.RealConnection.connectSocket(RealConnection.java:240)
       at okhttp3.internal.connection.RealConnection.connect(RealConnection.java:160) 
       at okhttp3.internal.connection.StreamAllocation.findConnection(StreamAllocation.java:257) 
       at okhttp3.internal.connection.StreamAllocation.findHealthyConnection(StreamAllocation.java:135) 
       at okhttp3.internal.connection.StreamAllocation.newStream(StreamAllocation.java:114) 
       at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:42) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) 
       at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:93) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) 
       at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) 
       at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:126) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) 
       at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:200) 
       at okhttp3.RealCall$AsyncCall.execute(RealCall.java:147) 
       at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32) 
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
       at java.lang.Thread.run(Thread.java:841) 
    Caused by: libcore.io.ErrnoException: isConnected failed: ENETUNREACH (Network is unreachable)
       at libcore.io.IoBridge.isConnected(IoBridge.java:208)
       at libcore.io.IoBridge.connectErrno(IoBridge.java:161) 
       at libcore.io.IoBridge.connect(IoBridge.java:112) 
       at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192) 
       at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459) 
       at java.net.Socket.connect(Socket.java:843) 
       at okhttp3.internal.platform.AndroidPlatform.connectSocket(AndroidPlatform.java:71) 
       at okhttp3.internal.connection.RealConnection.connectSocket(RealConnection.java:240) 
       at okhttp3.internal.connection.RealConnection.connect(RealConnection.java:160) 
       at okhttp3.internal.connection.StreamAllocation.findConnection(StreamAllocation.java:257) 
       at okhttp3.internal.connection.StreamAllocation.findHealthyConnection(StreamAllocation.java:135) 
       at okhttp3.internal.connection.StreamAllocation.newStream(StreamAllocation.java:114) 
       at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:42) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) 
       at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:93) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) 
       at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) 
       at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:126) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) 
       at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) 
       at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:200) 
       at okhttp3.RealCall$AsyncCall.execute(RealCall.java:147) 
       at okhttp3.internal.NamedRunnable.run(NamedRunnable.java:32) 
       at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
       at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
       at java.lang.Thread.run(Thread.java:841)

This OkHttp that I'm using is from Retrofit 2.4.0. Happens on both the emulator and the real device, but only on Kitkat. Also note that the exception is thrown immediately, not only after 10000 ms.

Is HttpURLConnection using IPv4 or IPv6? Looks like OkHttp is attempt IPv6. — Jesse Wilson, Nov 08 '18 at 10:29
@JesseWilson How can I figure this out? And can I force OkHttp to use IPv4? — stackzebra, Nov 08 '18 at 10:36
You can implement Dns and strip IPv6 addresses. Delegate to the Dns.SYSTEM class to get the full set then trim it. — Jesse Wilson, Nov 10 '18 at 03:30

score 6 · Accepted Answer · answered Nov 10 '18 at 09:44

I solved it! The real device was actually getting Javax.net.ssl.SSLHandshakeException, while the emulator was getting java.net.ConnectException. This StackOverflow discussion describes that there's a bug around TLS for pre-Lollipop devices. Javax.net.ssl.SSLHandshakeException: javax.net.ssl.SSLProtocolException: SSL handshake aborted: Failure in SSL library, usually a protocol error

So now I use this code from this answer: https://stackoverflow.com/a/50640113/9702500, it solves both the emulator exception and the device exception:

ConnectionSpec spec = new ConnectionSpec.Builder(ConnectionSpec.COMPATIBLE_TLS)
                .supportsTlsExtensions(true)
                .tlsVersions(TlsVersion.TLS_1_2, TlsVersion.TLS_1_1, TlsVersion.TLS_1_0)
                .cipherSuites(
                        CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
                        CipherSuite.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
                        CipherSuite.TLS_DHE_RSA_WITH_AES_128_GCM_SHA256,
                        CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
                        CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
                        CipherSuite.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
                        CipherSuite.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
                        CipherSuite.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
                        CipherSuite.TLS_ECDHE_RSA_WITH_RC4_128_SHA,
                        CipherSuite.TLS_DHE_RSA_WITH_AES_128_CBC_SHA,
                        CipherSuite.TLS_DHE_DSS_WITH_AES_128_CBC_SHA,
                        CipherSuite.TLS_DHE_RSA_WITH_AES_256_CBC_SHA)
                .build();
        OkHttpClient client = new OkHttpClient.Builder()
                .connectionSpecs(Collections.singletonList(spec))
                .build();
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl("https://tastedive.com")
                .addConverterFactory(GsonConverterFactory.create())
                .client(client)
                .build();

HttpURLConnection in Android working fine, but OkHttp gives "Network is unreachable" on Kitkat

1 Answers1