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I'm trying to figure out different ways the computer could be configured regarding DNS name resolution and network settings in general, when having multiple NICs (for instance one wired and other wireless) and a VPN connection (over the wired).

First question was which DNS server my computer would be using.

Each one of the 3 NICs have they own list of DNS servers to use, but in theory only one DNS server should be used, right?

I think, correct me if I'm wrong, that the computer would use the DNS servers of the first connection as is listed in the Adapters and Bindings section, right? If all DNS listed there (IP4 and IP6) are not reachable they would go to the next adapter, right? Reachable means reachable by the route print settings.

Googling it seems some people suggest that changing the Automatic metric property of Advanced TCP/IP Settings on a given connection would change the order of DNS servers to use. Is that true? I thought this setting only affects the route print table, IE only affects IP routing but not name resolution.

Regarding VPN, I assume the VPN connection is listed as [Remote Access connections] in Adapters and Bindings right? If not, what is [Remote Access connections]? Hopefully nothing to do with Office... :)

And finally the TCP/IP settings of the VPN use a different Ip Settings tab. There are two check boxes there that make me wondering... "Use default gateway on remote network" and below "Disable class based route addition". I guess this two settings only affects at the route print table right? Or it affects which DNS server my computer is going to use?

And last, what is the purpose of the Provider Order tab? Who is using that?

Thanks in advance,

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Can I ask what you're using to connect to the VPN? If using the in-built Windows connection, it's likely you will be using the VPNs DNS. –  Jeeva Aug 10 '12 at 9:32
    
It depends. Most of the clients I have currently use Juniper network connect, but I'm more interested in understanding in general all computer settings related to DNS name resolution than to figure out what my current configuration is doing –  Eduard Aug 10 '12 at 10:40
    
Ups, connecting with Juniper VPN I see a new NIC have been added in Network Connections. In Adapters and Bindings it is listed first. What is the purpose of "[Remote Access connections]" then? –  Eduard Aug 10 '12 at 10:45
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1 Answer

In regards to your question about DNS:

It depends on which NIC/configuration has priority.

In regards to your first question about NICs, routing, and priority:

1) Your computer will use the configurations of the NIC with the highest priority

2) Your computer will determine if the destination you're routing to is route-able through the interface that has the current priority

2)a) If the route is not available in the selected NIC it will migrate to the NIC that has the routing instructions for the destination

2)b) If there are no NICs with routing information for the destination, it will (sometimes) migrate to the next highest priority NIC

In regards to VPN and the custom built adapters:

These are virtual interfaces the VPN client applications build for routing purposes. This translates your network traffic through the virtual interface, to the VPN server.

In regards to the "Use default gateway on remote network" option:

When enabled, this option forces all local traffic on a VPN client to go through the VPN tunnel. This makes the computer "look" like it's on the same network as the VPN server (i.e. the office). If it is disabled, it will allow users to access office resources through the VPN and (theoretically) Internet traffic gets routed locally through the network you're currently connected from (If you're at home, then your home network. If you're in a hotel, then the hotel network).

In regards to "Disable class based route addition":

This option is for determining routing. You should leave this default option unless you have created specific routing instructions in your VPN tunnel.

In regards to the Provider Order tab:

This is for selecting the priority of your network interfaces. Generally speaking, you should move your VPN adapters toward the top. This will help alleviate issues when you are attempting to access resources in your office, because it makes the routing available at a higher priority (so it doesn't time out while the system is trying to figure out the routing tables).

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