[lvs-users] Windows Server configuration example for one arm NAT (single network) works.

Malcolm Turnbull malcolm at loadbalancer.org
Fri Aug 1 12:29:40 BST 2008

Forgot to add that this method works for Linux as well avoiding the
need to add a route for each host i.e. as follows:

Route configuration for Linux with one arm NAT mode:
When a client on the same subnet as the real server tries to access
the virtual server on the load balancer the request will fail. The
real server will try to use the local network to get back to the
client rather than going through the load balancer and getting the
correct network translation for the connection.
To rectify this issue we need to modify the local network route to a
higher metric:
route del -net netmask dev eth0
route add -net netmask metric 2000 dev eth0

NB. Replace with your local subnet address.
Then we need to make sure that local network access uses the load
balancer as its default route:
route add -net netmask gateway
metric 0 dev eth0

NB. Replace with your load balancer gateway
Any local traffic (same subnet) is handled by this manual route and
any external traffic is handled by the default route (which also
points at the load balancer).


Malcolm Turnbull.

Loadbalancer.org Ltd.
Phone: +44 (0)870 443 8779

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