Carry your existing VPN across a SIMSY network

Three steps to a working integration

1. STEP 01

   Add a private listener on your concentrator

   Use the existing private interface if there is one, or add a listener on the interface that faces your SIMSY breakout. The public listener stays exactly as it is, running in parallel while you prove the private path.

2. STEP 02

   Add a routing policy on SIMSY

   Create a routing policy that allows traffic from the SIM group to the concentrator's private address, with default-deny for everything else. From this point on, the SIM group speaks only to your VPN.

3. STEP 03

   Cut the public listener when you are ready

   Once devices are authenticating cleanly through the private breakout, take the concentrator's public interface off the internet at a moment of your choosing. The VPN itself carries on unchanged, now scoped to your own network.

# Illustrative - see API reference for current endpoints
import simsy

client = simsy.Client("your-api-key")

# Create a routing policy that sends this SIM's traffic to your
# concentrator's private address (not a public one). The route
# lives inside the SIMSY core.
policy = client.create_routing_policy(
    name="via-corp-vpn",
    default_egress="deny",
    routes=[
        {
            "dest_cidr": "10.20.0.10/32",   # your concentrator, private IP
            "action":    "allow",
        },
    ],
)

# Attach the policy to an endpoint group so every SIM in that
# group breaks out through the concentrator rather than to the
# open internet.
client.set_endpoint_group_policy(
    endpoint_group="corp-devices-uk",
    policy_id=policy.id,
)

The exact API surface is placeholder while the SIMSY routing endpoints stabilise. The shape (policy, dest CIDR, endpoint group) reflects how the finished endpoints will read.

Design decisions to fit into your set up.