Starlink failover on Peplink: a deployment guide

Starlink failover on Peplink: a deployment guide

Starlink failover on Peplink: a deployment guide

Starlink and Peplink are a natural pairing. Starlink provides a high-bandwidth, global satellite WAN link; Peplink provides the router that manages it intelligently alongside your other WAN links. Together, they give you a bonded or failover setup that keeps sessions alive when cellular drops, the satellite obstructs, or the fibre goes down.

This guide covers the practical steps: hardware wiring, Peplink WAN configuration, expected behaviour during handover, and the gotchas that catch people out in the field.

What you need

  • A Peplink router with at least two WAN ports (most models qualify; the Balance 310, BR2 Pro 5G, and MAX Transit Pro are common choices)
  • A Starlink terminal (Standard or Flat High Performance; both work the same way on the Peplink side)
  • Your secondary WAN: cellular (built-in or USB modem), fibre, or ADSL
  • A SpeedFusion subscription or InControl 2 licence if you want active bonding rather than failover

The Starlink terminal provides a DHCP address in the 192.168.100.0/24 range by default. Your Peplink WAN port will receive 192.168.100.x from the Starlink router.

Wiring it up

Standard setup (Starlink router in the path):

Starlink terminal → Starlink router (192.168.100.1) → Peplink WAN port

The Peplink WAN port should be set to DHCP. It will receive an IP in the 192.168.100.0/24 range. This is a double-NAT setup: your devices are NAT'd by the Peplink, and the Peplink WAN is NAT'd by the Starlink router.

For most outbound traffic, double-NAT works fine. For inbound connections or VPN endpoints that need a public IP, you need bypass mode.

Bypass mode (Starlink router disabled):

Starlink now supports bypass mode on the Standard and Flat HP terminals. In the Starlink app, go to Settings > Advanced > Bypass Mode. This puts the terminal into a transparent bridge mode. Your Peplink WAN port receives the public IP directly from Starlink.

Note: bypass mode disables the Starlink router's Wi-Fi and local DHCP. If you have devices connecting directly to the Starlink router, move them to the Peplink's network first.

Peplink WAN configuration

  1. Go to Network > WAN > WAN Connection. Select the WAN port connected to Starlink.
  2. Set Connection Method to DHCP.
  3. Set Priority. If Starlink is your primary link, set to highest priority (1). If cellular is primary and Starlink is backup, set Starlink to priority 2.
  4. Under Health Check: use HTTP health check against a reliable external host (not Starlink's own gateway). Use 8.8.8.8 or a Peplink SpeedFusion Hub endpoint. DNS health checks also work.
  5. Set the health check interval to 10 seconds and failure threshold to 3 for reasonably fast failover without false positives.

SpeedFusion bonding vs failover: which to use

Failover only is simpler and sufficient for most branch office or home setups. The Peplink monitors both WANs continuously; when the primary fails the health check, it switches all traffic to the backup. Active sessions drop briefly during the transition (typically 1-5 seconds depending on health check settings).

SpeedFusion active/active bonding keeps sessions alive across link transitions. The Peplink establishes a SpeedFusion tunnel to a PepVPN peer or SpeedFusion Cloud hub. Both WAN links carry traffic simultaneously. When cellular drops, traffic shifts instantly to Starlink within the tunnel without session interruption. The trade-off: SpeedFusion requires either a self-hosted PepVPN hub or a SpeedFusion Cloud subscription.

For maritime and mobile use cases where session drops are unacceptable (video calls, live streaming, command-and-control), SpeedFusion bonding is worth the extra cost. For branch offices with occasional Starlink backup, failover is sufficient.

Expected behaviour during WAN transitions

Cellular drops (Starlink takes over): - Failover mode: 10-30 second gap depending on health check thresholds. TCP sessions must be re-established by the application. - SpeedFusion mode: 0-2 second seamless transition. Application sessions survive.

Starlink obstruction event: Starlink latency spikes during obstruction events (trees, buildings, heavy snow). You may see latency increase from the typical 20-60ms to 500ms+ for 5-30 seconds. Peplink's WAN Quality algorithms detect this and can shift traffic to cellular automatically if you set a latency threshold. Go to WAN > WAN Quality and set Maximum Latency to, for example, 150ms. Traffic will move to cellular while Starlink recovers.

Starlink satellite handoff: Every few minutes, Starlink hands your connection from one satellite to another. This causes a brief latency spike (typically 200-600ms) with no packet loss. Most Peplink health checks will not trigger a failover for this. This is normal behaviour; do not set your health check thresholds aggressively low or you will see phantom failovers.

Common gotchas

CGNAT on cellular backup. Most UK mobile networks (EE, Vodafone, O2, Three) put data SIMs behind CGNAT by default. You do not get a public IP; you get a private address from the carrier's network. This means inbound connections and VPN endpoints listening on the cellular WAN will not work. Fix: request a static IP APN from your carrier (EE and Vodafone both offer these), or use SpeedFusion Cloud to anchor inbound connections at a Peplink hub with a public IP.

IPv6 from Starlink. Starlink provides IPv6 connectivity. If your LAN devices use IPv6 for outbound connections and cellular does not provide IPv6, IPv6 sessions will break on failover to cellular. Either disable IPv6 on the Peplink LAN or ensure your cellular WAN also has IPv6. For most business use cases, disabling IPv6 on the Peplink is the simpler fix.

Double-NAT and inbound VPN. If you run a VPN server on a device behind the Peplink and Starlink is in non-bypass mode, inbound VPN connections will fail because the Starlink router does not know to forward UDP/TCP to the Peplink WAN IP. Solution: use bypass mode, or move the VPN to a cloud endpoint (SpeedFusion Hub, WireGuard on a VPS) that the Peplink connects out to.

Starlink dish power consumption. The Standard dish draws 50-100W. The Flat High Performance draws 100-150W at startup. On 12V or 24V DC installations (vehicles, boats), size your power budget accordingly. Peplink routers themselves draw 10-30W depending on model.

Firmware compatibility. Peplink firmware 8.4.0 introduced dedicated Starlink health check improvements. If you are on older firmware, upgrade before deploying Starlink. The health check improvements reduce false-positive failovers during satellite handoffs.

Real-world performance expectations

On the Flat High Performance terminal (commercial/maritime), expect: - Download: 100-500 Mbps (variable, depends on satellite load) - Upload: 20-50 Mbps - Latency: 20-60ms under clear sky - During obstruction: latency spikes to 300-2000ms for seconds at a time

On the Standard terminal (residential/small business): - Download: 50-300 Mbps - Upload: 10-30 Mbps - Latency: 25-70ms

Cellular (4G on EE UK as reference): - Download: 30-150 Mbps - Upload: 10-50 Mbps - Latency: 15-40ms

In a SpeedFusion bonded setup, the combined throughput is roughly the sum of both links up to the Peplink router's SpeedFusion bandwidth ceiling. A Balance 310 handles up to 200 Mbps of SpeedFusion throughput; a MAX BR2 Pro 5G handles 400 Mbps.

Recommended hardware for Starlink + cellular setups

Single site, office or vessel: MAX BR1 Pro 5G (£939 RRP) — single 5G modem, one Ethernet WAN port for Starlink, SpeedFusion capable. Good for 1-5 users.

Multi-user vessel or branch office: MAX BR2 Pro 5G (£2,719 RRP) — dual WAN Ethernet + dual cellular modems. Bond Starlink + two cellular links simultaneously. Up to 50 users.

Large vessel or enterprise branch: Balance 310 5G (£1,879 RRP) — three WAN ports, 5G modem, desktop/rack form factor. Suitable for 20-100 users with full SpeedFusion bonding.

Get it set up right

We have deployed Starlink + Peplink on vessels, OB vans, and temporary-site deployments. The configuration is straightforward once you know the gotchas above. If you want a configuration review before you order, start a conversation. We will tell you exactly what to buy and how to wire it.