1. Download the Virtaulbox and install it.
2. Download the openwrt img on the OPENWRT website.
3. Convert img to VirtualBox format: vboxmanage convertfromraw--format VDI openwrt.img openwrt.vdi (in VirtualBox version 5.0.12 the " --format VDI "is at the end of command)
4. Set the eth0 to brige the network connection to the host and set up DHCP, which is connected to the extranet.
5. Set Eth1 to Interanet, set static static Ip,ip custom in OpenWrt such as 192.168.10.1 do not conflict with host IP.
6. The client machine is installed in VirtualBox for Windows XP and Windows 7, and for example VMS that span virtual machines are temporarily not possible because the network segment is different. Setting Eth0 to Interant and then manually setting the IP,DSN must also be set or there will be frequent wire break issues. If the IP of OpenWrt is 192.168.10.1 then the client's gateway and DNS are set to 192.168.10.1.
7. Install PPTP in OpenWrt,
OPKG Update
Opkg Install LUCI-PROTO-PPP
8. Restart the openwrt.
9. Then log in to the router, such as 192.168.10.1, to add PPTP dialing under Network---Interface.
10. Finally set up WAN-VPN in and out settings accept in network---firework.
This method can be used to set up multiple OpenWrt dial-up VPN, to achieve a single computer to dial multiple VPN scenarios.
A computer multi-dial VPN scheme, Openwrt+virtualbox