VPN and Android in China.
Despite the fact that Android is based on Linux, the situation with VPN in early versions of Android is deplorable. It's all the fault of Google's amazing sluggishness in terms of correcting some errors. Problems with VPN on older versions of Android actually two:
1. Encryption in PPtP does not work. At all. The connection is established, works for a while, then dies safely, and no data goes. This bug is well known, and even there is a big topic in the Google tracker for broken PPtP. There are reports that in versions 2.3.7 it was corrected, but I alas did not test, as it was updated.
2. Feature of L2TP/IPsec operation. The fact is that the installation of the connection key goes through key-storage. And when you put the key in storage, the application that added the key is taken into account. BUT, at the connection itself, the key request comes from the system user, and since the key was saved on behalf of the VPN client, any VPN launch with L2TP/IPsec fails. No key.
But not everything is so sad. In the new version of Android, Google announced a new API-VpnService. It allows you to implement your own VPN protocols and exchange traffic with the system through special interfaces ( in fact, through TUN). And everything seems to be great, but there was not without a barrel of tar in a spoonful of honey, namely-TUN-driver is missing on a whole army of devices:
- Amazon Kindle tablets;
— many devices from Sony;
— most Chinese tablets.
In General, if your device belongs to one of the listed classes of devices, most likely the VPN will not work for you.
