For a wired device on an eero, eero's slow-speed article gives the checklist. Check the cable type: Cat5 is limited to 100 Mbps, most Cat5e supports up to 1 Gbps, and Cat6 or better may be needed for faster links. Try a different cable, since damaged cables reduce speed even when the link looks active. Try a different Ethernet port on the eero if it has one, then connect the same cable and device to a different eero to rule out a port fault. Test with a second device on the same cable and port: if it gets expected speeds, the first device is the problem, and if the device's Ethernet adapter only supports 100 Mbps, speeds are limited regardless of cable or eero.
Before testing, turn off SQM in the app.
The checks in more detail
If speeds are low even wired to the primary eero, restart the primary eero by unplugging it for 30 seconds and waiting about a minute for solid white, swap the cable between the modem and the gateway and, if you have a spare eero, swap it in. Wired backhaul between eeros also needs good cable. If the whole network is slow, test straight from the modem as described in the network-slow guidance. Remember that a wired backhaul between eeros counts too: a slow or damaged cable between two eeros holds down every device behind the second one, so test each link.
If a device shows a 100 Mbps link light or negotiates 100 Mbps in its network settings, the cable is the first thing to change, since a damaged pair often drops from gigabit to 100 Mbps silently.
Differential
Likely causes of “eero mesh wifi Ethernet link is limited to 100 Mbps or disconnects”, and how to tell them apart
- 1
A Cat5 cable
What separates it The wired link is stuck at 100 Mbps because the cable is a Cat5 cable
How to confirm Use a Cat5e or Cat6 cable, since a Cat5 cable limits the speed to 100 Mbps
- 2
A damaged cable
What separates it The wired link is slow or drops because the cable is damaged
How to confirm Swap the cable for another one, and test the speed again
- 3
A 100 Mbps adapter
What separates it The speed is capped on one device because its Ethernet adapter only runs at 100 Mbps
How to confirm Check the Ethernet adapter on the device, since a slow adapter limits the speed
- 4
A bad port
What separates it One port is slow because that port on the eero has a fault
How to confirm Try another port, or another eero, to see whether the first port is at fault
- 5
SQM
What separates it The speed test reads low because Smart Queue Management is limiting it
How to confirm Turn SQM off for the test, since it can limit the speed test result
Before you touch a setting
Record this first — changing settings destroys the evidence
- The type of cable and its length
- The port and the device adapter speed
- The speed you measure on another wired device
- The speed you measure straight at the modem
Try in this order
0 of 7 completedCheck the cable
ReversibleCheck the cable type, and use Cat5e or better, since Cat5 cannot go beyond 100 Mbps.
Swap the cable
ReversibleSwap the cable for another one that you know is good, and then test the speed again.
Change the port
ReversibleChange the port by using another Ethernet port, to see whether the first port is at fault.
Swap the eero
ReversibleSwap the eero for another unit and test the other one, to find out whether it is the hardware.
Test another device
ReversibleTest another device on the same cable, to rule out the Ethernet adapter of the first one.
Turn off SQM
ReversibleTurn off SQM in the settings, and then test again, because it can limit test results.
Restart the primary eero
ReversibleRestart the primary eero by unplugging it for thirty seconds and plugging it in again.
Model-specific
What is true of this model and not of its siblings
- Ports
- The Max 7 has 10 Gbps class Ethernet, the eero 6+ and Pro 6 have gigabit ports and the Beacon has none.
- Outdoor 7
- The Outdoor 7 is the outdoor-rated model; check its Ethernet and power arrangement in the eero product page.
- Other models this page answers
- These steps also fit the eero Pro 6E.
Stop boundary
When this stops being a self-service repair
- !If a known-good cable and port still cap at 100 Mbps, contact eero support
- !If only one port is slow, use another port and note it
- !If the modem is slow direct, call the provider
Evidence ledger
Sources behind this answer
SQM, wired and wireless single-device checks.
Isolating the ISP, the modem and the gateway.
Ethernet ports and switches.
Wired eero links.
The company and its products.
Exact questions
Common questions
What speed does Cat5 give?+
A Cat5 cable gives a speed of up to 100 Mbps, and no more than that.
What about Cat5e?+
Most support up to 1 Gbps.
Do I need Cat6?+
For faster links you need Cat6 or better, so yes, use it for multi gigabit speeds.
Can a device cap the speed?+
Yes, a 100 Mbps adapter does.
How do I test a port?+
Move the cable and device to another eero.
Does SQM matter?+
Yes, SQM matters, since it can limit the results of a speed test.
Does the Beacon have Ethernet?+
No, the Beacon does not have an Ethernet port, so it works only over wifi.
How do I add ports?+
Add ports with a switch, which you connect to the eero by one Ethernet cable.