On an eero 6+ the wired-speed question is a chain question: modem, cable, eero, switch, device. Every link negotiates its own speed and the slowest one wins. The eero 6+ has two gigabit Ethernet ports, so it is not the limit on a gigabit plan, but an old unmanaged switch, a Cat5 patch cable, a docking station or a device's adapter can each hold a wired device to 100 Mbps.
A good habit is to test at each step: plug a laptop into the ISP's box and run a speed test, then into the eero gateway, then into the far end of the wired run. Where the speed drops is the faulty link. A wired node, a switch behind the gateway and a long run in the wall are the places where owners find the 100 Mbps link. Replace the cable first, then the switch.
Differential
Likely causes of “eero 6+ Ethernet link is limited to 100 Mbps or disconnects”, and how to tell them apart
- 1
An old unmanaged switch
What separates it Devices behind the switch run at 100 Mbps
How to confirm Replace it with a gigabit switch
- 2
A Cat5 or damaged cable in the wall or patch
What separates it One wired device is limited
How to confirm Test with a short known-good cable at the device
- 3
A dock or adapter at 100 Mbps
What separates it A laptop through a dock is slow wired
How to confirm Use the laptop's own port or a gigabit adapter
- 4
A wired node linked at 100 Mbps
What separates it A wired eero node shows a low link rate
How to confirm Replace the cable between the gateway and the node
- 5
A device setting
What separates it The device's network card is set to 100 Mbps
How to confirm Set it to auto-negotiate
Before you touch a setting
Record this first — changing settings destroys the evidence
- Speed tests at the ISP box, the eero gateway and the far end
- The cable categories and the switch model
- Which device and port show 100 Mbps
- Whether a wired node is involved
Try in this order
0 of 6 completedPlug a laptop into the ISP's box and test
ReversibleUse a short cable and run a speed test; this shows what the line delivers before the eero is involved.
Move the same laptop to an eero gateway port
ReversibleUse the same short cable on one of the gateway's two gigabit ports; if the speed falls here, the eero's port or the WAN link is the limit.
Test at the far end of the wired run
ReversiblePlug the laptop into the wall socket where the slow device lives; a drop at this step means the in-wall cable or a switch is the limit.
Replace the suspect cable first, then the switch
ReversibleA Cat5e or Cat6 patch cable costs little; an old unmanaged switch is next, replaced with a gigabit one.
Check the device's adapter settings
ReversibleIn the device's network settings set the adapter to auto-negotiate speed rather than a fixed 100 Mbps.
Restart the chain in order
ReversibleModem, eero gateway, switch, then devices, giving each time to settle.
Model-specific
What is true of this model and not of its siblings
- The slowest link wins
- A single 100 Mbps cable or port anywhere in the path limits everything behind it to 100 Mbps, even when the line and the eero are gigabit.
- A dock is a link too
- A laptop on a dock with a 100 Mbps port will read slow wired even on a perfect network.
Stop boundary
When this stops being a self-service repair
- !If a short known-good cable at the gateway still gives 100 Mbps, contact eero support
- !If the wall run is the limit, an electrician or the installer must replace the cable
- !If only one device is slow, check its adapter
Evidence ledger
Sources behind this answer
Discussion of what limits eero speeds on a gigabit plan.
An owner whose eero sees only 100 Mbps on a gigabit line.
An owner puzzled by a data rate of 100.
Exact questions
Common questions
Can the eero 6+ itself be the 100 Mbps link?+
Rarely; its two ports are gigabit, so test the cable, switch and device first.
Does a long cable slow Ethernet?+
Within 100 meters of good cable, no; a poor or damaged cable does.