DrayTek VPN Solution

Outline

• What is VPN• What does VPN Do• Supported VPN Protocol• How Many Tunnels does Vigor Support• VPN Application• Special VPN Application• CVM (Central VPN Management)• Trouble Shooting

What is VPN

• A virtual private network (VPN) extends a private network across a public network, such as the Internet. It enables a computer to send and receive data across shared or public networks as if it were directly connected to the private network, while benefiting from the functionality, security and management policies of the private network.

http://en.wikipedia.org/wiki/Virtual_private_network

http://en.wikipedia.org/wiki/Virtual_private_network

What is VPN

What does VPN Do

• Host to LAN allow employees to securely access their company's intranet while traveling outside the office.

• Similarly, VPNs securely and cost-effectively connect geographically disparate offices of an organization, creating one cohesive virtual network. We call it as LAN to LAN.

http://en.wikipedia.org/wiki/Virtual_private_network

Supported VPN Protocol

• PPTP (TCP 1723)• L2TP (UDP 1701)• IPsec (UDP 500)• L2TP over IPsec• SSL VPN (TCP 443)• mOTP

How Many VPN Tunnel does Vigor Support

Vigor Model IPsec/PPTP/L2TP SSL

Vigor2110 2 N/A

Vigor2130 2 N/A

Vigor2912 16 N/A

Vigor2920 32 N/A

Vigor2925 25 25

Vigor2930 100 30

Vigor2950 200 10

Vigor2960 200 20

Vigor3200 Series 64 10

Vigor3300 Series 200 NA

Vigor3900 500 (PPTP/L2TP 200) 20

How Many VPN Tunnel does Vigor Support

Vigor Model IPsec/PPTP/L2TP SSL

Vigor2710 2 N/A

Vigor2760 2 N/A

Vigor2830 32 10

Vigor2850 32 10

Vigor2860 32 10

VPN Application

• LAN to LAN• Host to LAN

– PPTP/L2TP/IPsec/L2TP over IPsec– SSL VPN– mOTP

• VPN Trunk

LAN to LAN

172.17.1.0/24 192.168.1.0/24

Host to LAN

• Client site OS could be– Windows (may use Smart VPN client)– Mac OS/iOS– Android– Ubuntu

SSL VPN

• SSL Tunnel– TCP port 443

• SSL Application• SSL Proxy

http://www.draytek.com.tw/index.php?option=com_k2&view=itemlist&task=category&id=129:ssl-vpn&Itemid=293&lang=en

SSL VPN

SSL VPN

mOTP: Mobile One Time Password

VPN Trunk-Load Balance

VPN Trunk-Backup

Special VPN Application

• Change default route to this VPN tunnel• Apply VPN Tunnel as Interface for L/B Policy• VPN backup when specified WAN drops• Packets trigger to establish the VPN tunnel• Add more network into Phase 2 SA

Change Default Route to VPN tunnel

• Enable VPN default route

• Go via VPN tunnel for local service

Apply VPN Tunnel as Interface for L/B Policy

• How to Use Load-Balance/Route Policyhttp://www.draytek.com.tw/index.php?option=com_k2&view=item&id=5181&Itemid=293&lang=en

VPN Backup when Specified WAN Down

Add More Network into Phase2 SA

CVM

CVM

• How to Use Central VPN Managementhttp://www.draytek.com.tw/index.php?option=com_k2&view=item&id=5293&Itemid=293&lang=en

Trouble ShootingVPN is up but Traffic cannot pass to

remote network?

What to Do?

• Check Routing Table• Use ping to diagnose• Use trace route to diagnose• Check Firewall Rule

Check Routing Table

• Check Dial-Out Vigor's Routing table• Check Dial-In Vigor's Routing table– If the route to remote VPN network doesn't

exist, check TCP/IP Network Setting in VPN LAN to LAN profile. – If the route to remote VPN network exists,

check if the host can respond ping.

PPTP Dial Out

PPTP Dial In

IPsec Dial Out

IPsec Dial In

Use Ping to Diagnose

• Ping to host from its Local Router– If Local Router cannot get ping response

from the host, check the firewall setting on the host.

• Find a host that can respond ping from its Local Router, and then ping the host from Remote Router.

Ping Diagnostic

Check ARP Table

Use Trace Route to Diagnose

• Use command “tracert -d destination IP” to check if the packet is sending through the right gateway.

Check Firewall Rule

• Check Firewall Rule and see if the packet to remote VPN network is blocked by firewall rule.

Case Study

Case Study

• Router A has two networks connected, which are 192.168.1.0/24 and 192.168.2.0/24.

• Router B has one network connected, which is 192.168.139.0/24.

• Computer with IP 192.168.139.10 can ping IP 192.168.1.10, but cannot ping IP 192.168.2.10.

• What could we do?

• Use Trace Route on Computer with IP 192.168.139.10 to destination IP 192.168.2.10.

• Result: The packet is routed to the Internet?!

Step1:

• Check Router B's Routing Table.• Result: There is no Route to 192.168.2.0/24 on

Router B.

Next Step:

• Add Route 192.168.2.0/24 via More option in VPN LAN to LAN Profile.

• Then disconnect and reconnect VPN.• Result: Router B has route to network

192.168.2.0/24 now.

Next Step:

• Use Trace Route on Computer with IP 192.168.139.10 to destination IP 192.168.2.10 again.

• Result: The packet is stopped at IP 192.168.1.1.

Next Step:

Next Step

Check Routing Table on Router A with IP 192.168.1.1.

Result: Route A has Static Route – to destination 192.168.2.0/24 via 192.168.1.15.

• Try to ping IP 192.168.1.15 from Router A.• Result: No ping response from IP 192.168.1.15

Next Step:

• Check Router A's ARP Table.• Result: There is no ARP for IP 192.168.1.15.It seems the host isn't connected to Router A!

Next Step:

• Check the Router setting that is connected between Router A and network 192.168.2.0/24.

• Result: The correct IP is 192.168.1.13!

Next Step:

Correct the Static Route setting from Router A then use Trace Route on Computer with IP 192.168.139.10 to destination IP 192.168.2.10 again. Result: It succeeds!

Next Step:

Application Note

• When VPN tunnel is established, why can't I access any host in the remote subnet ? - http://www.draytek.com.tw/index.php?option=com_k2&view=item&id=1279&Itemid=293&lang=en