An eero 6 that reports only 100 Mbps on a gigabit line is the single most common eero complaint in the community threads, and the cause is nearly always the cable. The eero 6 has two gigabit Ethernet ports, and one owner on Frontier fiber who got only 100 Mbps in the app was told the cable between the ISP's box and the eero is probably Cat5, which is limited to 100 Mbps, and that a Cat5e or Cat6 cable fixes it.
The rule is that the slowest link in the chain sets the speed, so a Cat5 cable, a damaged one with a broken pair, an old unmanaged switch or the other device's network card can each pull a gigabit link down to 100. The checks are quick: swap in a known-good Cat5e or Cat6 cable, try both ports on the eero, test with a different device, and if the eero still negotiates 100 Mbps, connect it to the LAN port of the ISP's router in bridge mode and see whether the link comes up at gigabit.
Differential
Likely causes of “eero 6 Ethernet link is limited to 100 Mbps or disconnects”, and how to tell them apart
- 1
A Cat5 or damaged cable between the modem and the eero
What separates it The app or a speed test shows about 100 Mbps
How to confirm Replace it with a Cat5e or Cat6 cable and check both ends click into the ports
- 2
The other end negotiating 100 Mbps
What separates it The ISP's box or a switch is old
How to confirm Try a different port on the ISP's box, or connect the eero through a gigabit switch
- 3
A faulty port on the eero
What separates it Both cables give 100 Mbps on one port and gigabit on the other
How to confirm Use the working port as WAN; the eero 6 has two
- 4
The wired device's own network card
What separates it A laptop or console only reaches 100 Mbps wired
How to confirm Test with another device; some adapters and old docks are 100 Mbps
- 5
Confusing the data rate shown for a node with the internet speed
What separates it The app shows 100 for a mesh node while the line is gigabit
How to confirm Run a speed test on a wired device, not from the node's data rate
Before you touch a setting
Record this first — changing settings destroys the evidence
- The cable category printed on its jacket
- The ISP and the ISP box model
- Whether both eero ports give the same result
- The speed from a wired laptop on a known-good cable
Try in this order
0 of 6 completedCheck the cable category
ReversibleRead the print on the cable jacket: Cat5e, Cat6 or better carry gigabit; plain Cat5 does not.
Swap in a Cat5e or Cat6 cable
ReversibleReplace the cable between the ISP's box and the eero, and press both plugs in until they click.
Try both ports
ReversibleMove the cable to the eero's other Ethernet port and compare.
Test with a wired laptop
ReversiblePlug a laptop directly into the ISP's box with the same cable and run a speed test; if it reaches gigabit, the eero side is the limit.
Restart the chain in order
ReversibleSwitch off the modem, the eero and the switch, then power on in that order, waiting for each to settle.
Try bridge mode as a diagnostic
ReversibleConnect the eero to the LAN port of the ISP's router and set the router to bridge or the eero to bridge; owners report this can bring the link up at gigabit.
Model-specific
What is true of this model and not of its siblings
- The eero 6 hardware
- Two gigabit Ethernet ports, Wi-Fi 6 and a mesh of nodes, so the wired link to the modem is the first thing to check on a speed complaint.
- Why Cat5 survives
- Old Cat5 cable looks identical to Cat5e, so a cable that came with a previous router can be the hidden limit.
Stop boundary
When this stops being a self-service repair
- !If the eero negotiates 100 Mbps on two good cables and two ports, contact eero support
- !If the ISP's box negotiates 100 Mbps with a good cable, call the ISP
- !If only one wired device is slow, the cable or card on that device is the cause
Evidence ledger
Sources behind this answer
An owner whose eero sees only 100 Mbps on a gigabit line.
Discussion of what limits eero speeds on a gigabit plan.
An owner puzzled by a data rate of 100.
eero's product page for the eero 6 and its ports.
Exact questions
Common questions
Why does my eero 6 only show 100 Mbps?+
Usually a Cat5 or damaged cable; a Cat5e or Cat6 cable restores gigabit.
How many Ethernet ports does the eero 6 have?+
Two gigabit ports, one of which can be the WAN port.
Is the data rate in the app my internet speed?+
No, it is the link rate between nodes or devices; run a speed test on a wired device.
Could my ISP box be the problem?+
Yes, an older box or port can negotiate 100 Mbps; try another port or ask the ISP.