Google Cloud Messaging not working on 4.1.2 devices on a corporate network

Question

I\'ve implemented a simple GCM client and server. The client uses the current GCM client APIs (not the deprecated helper library). The server (C# & .NET) follows the cor

Answer 1

I've finally figured out what the problem is. The corporate firewall is blocking traffic on the native GCM port of 5228. (5229 and 5230 are also mentioned with relation to GCM but we're not seeing any attempted traffic on those ports at all.) This much is well documented elsewhere (just Google GCM port 5228).

What I can't find clearly documented anywhere, but we've figured out from our server logs and from running Connection Tracker on the handsets, is that newer versions of Android fall back to using port 443 (the standard HTTPS port) which most firewalls allow traffic through by default. This is how our devices running newer Android versions are working even behind the firewall. I don't know precisely what Android version introduced this port 443 fallback, but it's somewhere between 4.1.2 (not working) and 4.3 (working).

Answer 2

I don't see the manifest entries above, but I ran into the exact issue a few days ago, the manifest package must match the C2D_MESSAGE permission package. ie.

    <?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.foo.bar"
    android:versionCode="8"
    android:versionName="3.1">

...

<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE"/>
<uses-permission android:name="android.permission.GET_ACCOUNTS"/>
<permission android:name="com.foo.bar.permission.C2D_MESSAGE"
    android:protectionLevel="signature" />
<uses-permission android:name="com.foo.bar.permission.C2D_MESSAGE" />

In my case the declared package did not match in order to provide an upgrade path for a previous version of the application.