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Scenario 1 — Flat site network with DHCP#

Level: basic · Devices: EdgeBox, RevPi (eth0)

Flat site network with DHCP

When this applies#

  • All devices Octave needs — PV inverter, EV charger, meter — are in one subnet.
  • The site router hands out addresses automatically (DHCP).
  • The device reaches the internet through that same router.

This is the factory default for eth0 and the simplest possible setup.

What the device needs#

Setting Value
Mode DHCP
DHCP DNS mode Extend DHCP-provided DNS (default)
DNS servers Optional — one public resolver as a backup, e.g. 1.1.1.1

Configure#

  1. Open Network Configuration → Edit configuration → Primary interface (eth0).
  2. Set Mode to DHCP.
  3. Leave DHCP DNS mode on Extend, unless the site's DNS is broken or blocked (see below).
  4. Press Test. DHCP offer received, Gateway responds on eth0 and every DNS server reachable row must pass.
  5. Press Apply.

eth0 in DHCP mode

eth0 in DHCP mode

Extend or Override DNS?#

Mode What happens Use when
Extend Your DNS servers are added after the ones from DHCP Almost always. The site's DNS stays first.
Override Only your DNS servers are used; the DHCP ones are ignored The site's DNS server doesn't resolve internet names, or blocks them

Note

Linux uses at most 3 DNS servers. In Extend mode, if DHCP already hands out three, your extra entries are dropped. Use Override when you need to be sure your server is used.

Check it#

  1. Under Current network configuration → Primary interface (eth0): a live IPv4 address in the site range and a lease from the expected DHCP server.
  2. Connectivity card: all green.
  3. On the Troubleshooting page, run Connectivity to each site device and Port / Service Scan with the Modbus preset.

Good to know: what happens when DHCP fails#

In DHCP mode the device never falls back to a fixed subnet. It recovers in this order:

  1. DHCP — the normal source of addressing.
  2. Previous lease reuse — if the DHCP server is briefly unavailable, for example after a site-wide power cut, the last valid lease is reused.
  3. IPv4LL (169.254.x.x) — if there's no previous lease, a link-local address is used.
  4. Automatic recovery — DHCP keeps retrying and takes over as soon as the server is back.

Warning

The address can change. A DHCP address can change after a router replacement or lease expiry. If other systems — a SCADA, a firewall rule — need the Octave device on a fixed address, ask the site to reserve the address in their DHCP server, or use Scenario 2 — Static IP.