We have installed an IPVPN network between our three offices. This will replace the existing links, that are comprised of Internet links with VPNs setup on a firewall at each office. Each office has a separate IP subnet.
The default gateway for the network is set to one of the firewalls via a system policy.
There needs to be a period when the existing links continue to be used for Internet access, while all traffic between our offices is sent via the IPVPN.
I need to understand the options that are available to me to implement. My initial thought was to create a routing table entries on all machines for each destination subnet.
I am not sure if this is the best way to implement the solution, as it would mean updating each machine and I am not sure of the order of precedence, ie, does the routing table entry override the default gateway?
We are using Hyper-V, with Windows Server 2003 guests, physical Windows Server 2008 R2 and Server 2003 machines, Windows/XP client (slowly being replaced) and Windows 7 Pro machines.
I am considering testing the changes by initially changing only one PC at each site, but I do not know how I can prove that the inter-office traffic is indeed using the IPVPN.