Set up a VPN Server (PPTP) on AWS

1. Create a EC2 instance using Ubuntu 14.04.
2. In Secure Group Inbound Rules, add a SSH Rule(TCP, Port 22, 0.0.0.0/0) and a Custom TCP Rule(TCP, Port 1723, 0.0.0.0/0).
3. Optional: Associate a Elastic IP with the instance.
4. SSH into the instance.
5. sudo apt-get install pptpd.
6. sudo vim /etc/pptpd.conf. Uncomment localip 192.168.0.1 and remoteip 192.168.0.234-238,192.168.0.245.
7. sudo vim /etc/ppp/pptpd-options. Uncomment ms-dns and ms-wins. Change the IP to Google's DNS like this:

ms-dns 8.8.8.8
ms-dns 8.8.4.4

#...

ms-wins 8.8.8.8
ms-wins 8.8.4.4

8. sudo vim /etc/ppp/chap-secrets. Add VPN users in this format <username> pptpd <passwd> *.
9. sudo vim /etc/sysctl.conf. Uncomment net.ipv4.ip_forward=1.
10. sudo /sbin/sysctl -p.
11. sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE.
12. sudo vim /etc/rc.local. Add iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE before exit 0.
13. sudo /etc/init.d/pptpd restart.

OSX Usage

1. Go to System Preferences > Network.
2. Click the + button. Choose VPN as interface. PPTP as VPN Type. And enter a name you can understand. Click Create.
3. Enter your instance's Public IP in Server Address.
4. Enter your <username> in Account Name.
5. Click Authentication Settings. Choose Password and enter your <password>.
6. Click Advanced. Check Send all traffic over VPN connection. Click OK.
7. Click Apply.
8. Click Connect.
9. You are good to go.

iOS Usage

1. Go to Settings > General > VPN.
2. Touch Add VPN Configuration....
3. Choose PPTP.
4. Enter any name in Description.
5. Enter your instance's Public IP in Server.
6. Enter your <username> in Account.
7. Enter your <password> in Password.
8. Turn on Send All Traffic.
9. Save.
10. Switch on the VPN connection.
11. You are good to go.