VPN route table population

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fran1942

82 posts

Master Geek

Trusted

#152328 23-Sep-2014 19:29

Hello, when you connect to a VPN via your PC client, often your computer's route table gets populated with all the routes that are part of that VPN connection.
I am just wondering what the mechanism is that populates your route table i.e. is it the VPN client that does it, or is it some protocol from a server on the VPN etc. ?
Thanks for any info.

markg1275

24 posts

Geek
+1 received by user: 4

#1134882 23-Sep-2014 19:40

Hi, many clients like the Cisco and sonicwall VPN clients install addional network adaptrers on the client machine. Its these that when the VPN connection is established inject routes into the route table as directly connected networks in the case of split tunnels or as a default route for tunnel all mode connections.

fran1942

82 posts

Master Geek

Trusted

#1134960 23-Sep-2014 21:11

thanks for that, but where do the network adapters get the routes from that they inject ?

Thank you.

markg1275

24 posts

Geek
+1 received by user: 4

#1135001 23-Sep-2014 21:31

They are provided as part of the phase 2 negotiations normally by the remote gateway/firewall. Phase 1 is normally basic authentication such as IP address and psk etc. But many VPNs require the client to already have this information. Normally a network admin would distribute this configuration to the machines.

Its this hastle of configuration that's made SSL VPNs popular and the client and it's configuration are destribuated via a hosted web portal. If the admin changes the secured networks no reconfiguration is needed to the client machines, they just login to the portal and get the new settings.