Your modem has internet (the Online light is solid), but your router shows no internet connection. This is a very specific problem — the router and modem aren't communicating properly. Here's how to fix it.
Step 1: Verify Modem Has Internet
- Disconnect the router from the modem
- Connect a computer directly to the modem with an Ethernet cable
- If you get internet → modem is fine, problem is router configuration
- If no internet → the modem itself has an issue (call ISP)
Step 2: Check Cable and Ports
- Use an Ethernet cable from modem to router's WAN/Internet port
- The WAN port is usually a different color (yellow) or labeled "Internet/WAN"
- Do NOT plug into a LAN port — that won't work
- Try a different Ethernet cable — cables can be bad
- Make sure the cable clicks firmly into both ports
Step 3: Restart Modem (Critical Step)
- Unplug modem (and router)
- Wait 60 seconds
- Plug in modem only → wait until Online light is solid (3-5 min)
- Now connect the Ethernet cable from modem to router WAN port
- Plug in router → wait 2-3 minutes
Why this is critical: The modem caches the MAC address of the last device connected. If you changed routers or connected a computer directly, the modem needs to be restarted to accept a new device.
Step 4: Check Router WAN Settings
- Access router admin panel (connect via Ethernet to LAN port → open 192.168.1.1)
- Go to WAN/Internet Settings
- Check the Connection Type:
- DHCP (Dynamic IP) — most cable ISPs (Xfinity, Spectrum, Cox)
- PPPoE — DSL providers (AT&T, CenturyLink) — requires username/password from ISP
- Static IP — business connections
- If unsure, try DHCP first — it's the most common
Step 5: Clone MAC Address
Some ISPs bind your internet to a specific device's MAC address:
- In router admin: WAN Settings → MAC Clone
- Select "Clone from Current Computer" (if it previously worked directly)
- Or enter the old router's MAC address manually
- Save and reboot the router
Step 6: Check for Double NAT
If your modem is a gateway (modem + router combo), you may have double NAT:
- Option 1: Put the gateway in bridge mode (disables its router function)
- Option 2: Set your new router as an access point instead of a router
- Option 3: Connect to a LAN port on the gateway instead of WAN port on the new router
Step 7: Contact ISP
- If you have a new router, the ISP may need to register/provision it
- Some ISPs (Xfinity, AT&T) require the router's MAC address to be on their system
- Ask the ISP to send a refresh signal to the modem
- Verify your account is active and in good standing
Frequently Asked Questions
Why won't my router connect to my modem?
Common causes: (1) Ethernet cable is in the wrong port (should be WAN/Internet port on router), (2) Modem needs to be restarted to release previous DHCP lease, (3) ISP requires MAC address registration, (4) Ethernet cable is damaged, (5) Modem is in bridge mode but router isn't configured for PPPoE, (6) New router — ISP may need to provision it.
Which port on the router connects to the modem?
Connect the modem to the router's WAN port (also called Internet port). It's usually: a different color (yellow is common), labeled WAN or Internet, physically separated from the LAN ports. The LAN ports (usually 4 of them) are for connecting computers, gaming consoles, etc.
Do I need to restart the modem when connecting a new router?
YES — this is the most overlooked step. The modem remembers the MAC address of the last connected device. When you connect a new router, the modem must be power cycled so it learns the new router's MAC address. Unplug modem for 60 seconds → plug in → wait 3 minutes → then connect router.
My router shows 'No Internet' after connecting to modem — why?
The modem has internet but the router can't access it. Check: (1) WAN connection type in router settings (should be DHCP for most ISPs), (2) Some ISPs use PPPoE — you need to enter a username/password in router settings, (3) ISP may have MAC filtering — clone the old router's MAC address.
Can any router work with any modem?
Generally yes, as long as the modem isn't a gateway (modem + router combo). If you're adding a separate router to a gateway, you'll get double NAT issues. Either: (1) Put the gateway in bridge mode, or (2) Set up the new router as an access point. Check compatibility on your ISP's approved device list.
Router Still Can't Connect to Modem?
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