Prepare your network for DHCP
Before you start
- You need the
adminrole and access to the Linux host. - You need a running node with the SQLite store.
- You need a copy of the current DHCP options, reservations and leases.
CAUTION: Two independent DHCP servers on one subnet can assign the same address. Keep the current service active until cutover. Stop it before you activate kudurru.
1. Plan the addresses
Record these values before you open the wizard. These example addresses match the screenshots. Replace them with your own network values.
| Item | Example | What to check |
|---|---|---|
| Scope name | lan | A stable name for the subnet |
| Host interface | eth0 | An existing interface on the client network |
| Server address | 192.0.2.2 | Already assigned to that interface; fixed and outside the pool |
| Client subnet | 192.0.2.0/24 | The network that contains the clients |
| First and last address | 192.0.2.100 to 192.0.2.199 | Free addresses inside the subnet |
| Router | 192.0.2.1 | The gateway for the clients |
| DNS server | 192.0.2.2 | Your node, reachable on UDP and TCP port 53 |
| Domain name | lan.home.arpa | A dedicated domain for lease names |
Keep static addresses outside the pool. Account for leases that the old server already issued. Use a nonoverlapping pool if you cannot import those leases.
2. Prepare the host
Choose the instructions for your deployment:
| Deployment | Required preparation |
|---|---|
| Docker on Linux | Build the DHCP image and use host networking |
| Linux package with systemd | Add the capability drop-in |
| Kubernetes | Use the separate relay and LoadBalancer guide |
The published Docker image lacks the file capabilities that DHCP needs.
Build from a source checkout with make docker-dhcp, then follow the host guide's run command.
Keep the existing data volume and secret files when you replace a container.
The dashboard cannot assign a host address or grant capabilities. Direct clients need broadcast connectivity on the selected interface. A published Docker UDP port alone does not provide it.
Check the result
- Run
ip -4 addr showon the host. - Find the fixed server address on the interface you plan to select.
- Confirm that the node uses the DHCP-capable image or the systemd drop-in.
- Confirm that you can stop the old DHCP service during cutover.
For VLANs or routed clients, read Multiple subnets and relays.