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How VPN automatic tunnel type works

  • Статья

RAS supports 3 types of tunnels namely Point to Point Tunneling Protocol (PPTP), Layer 2 Tunnelingu Protocol (L2TP) and Secure Socket Tunneing Protocol (SSTP) for connecting to work from home securely. When connecting from home you have option to either use automatic tunnel or PPTP, L2TP or SSTP tunnel.

To select the tunnel type open "Network and Sharing Center" and goto "Manage network connections". Select the VPN connection and right click on Properties. Now goto "Networking" tab and select the tunnel type under "Type of VPN".

Different tunnel types are tried depending on whether VPN server configured is IPv4 address, IPv6 address or host name. To configure VPN server open "Network and Sharing Center" and goto "Manage network connections". Select the VPN connection and right click on Properties. Now goto "General" tab and enter the VPN server’s name or IP address in "Host name or IP address of destination".

1. IPv4 address

Four options are shown for tunnel type viz. Automatic, PPTP, L2TP and SSTP. If Automatic is chosen then PPTP is tried first then L2TP and SSTP in that order. Once the connection is successfully made with one kind of tunnel then this tunnel type is remembered and next time when the connection is attempted that tunnel is tried first. If it fails with this tunnel then again the other tunnel types are tried.

2. IPv6 address

For IPv6 only L2TP and SSTP are supported. Hence, only L2TP and SSTP will show up under tunnel options.

3. Host Name

Three options are shown for tunnel type viz. Automatic, PPTP, L2TP, SSTP. If Automatic tunnel type is chosen tunnels that can be tried is determined by the DNS resolution of the VPN server name. If the hostname resolves to IPv6 address then L2TP ans SSTP will be tried in that order and if the name resolves to an IPv4 address then the behavior remains the same as above for IPv4 address.

It is recommended to set the tunnel type as Automatic so that the connection can be attempted on all the available tunnel types.

Rama Krishna Amaravadi
Development Lead
RRAS, Windows Enterprise Networking

[This posting is provided "AS IS" with no warranties, and confers no rights.]