Re: router R6400 not connet with modem CM1200


router R6400 not connet with modem CM1200


I have Xfinity internet in my house and I have my router R6400 and modem CM1200 and I have been performed the power steps and changed the internet cables, but my router still won't connect to the internet. If I connect the computer or the Apple TV to the modem directly they work, but not the router. What another step I can perform?

Model: R6400|AC1750 Smart WiFi Router
Message 1 of 3

Re: router R6400 not connet with modem CM1200

What all is plugged into the CM1200? It has 4 ethernet ports but only 1 is usable for most home users. This isn't true if you're doing wan port link aggregation (not available on the R6400) or if you have an ISP that allows multiple IP address to the modem. Most don't. 

You need to have the R6400 plugged into port 1 on the cm1200 and only the router plugged in. Then follow this procedure.

Power off both devices. 
Power on the modem with nothing plugged in. give it a minute or 2.

Then plug the modem into wan port on the router.

Then power on the router. give it a minute or 2 to fully boot.



Another thing to check is to see if port aggregation was turn on in the CM1200. This can cause issues if you're not using it. If you can log into the modem and disable this, perfect. If you can't log into the modem to change this, a factory reset will default it back to off. To do so, push and hold reset while powered up for 7-10 seconds or until the lights change. 

Current setup: CAX80->Trendnet TEG-S380->GS716T-> RBK752->pi-hole
1.4gig download/50mbps upload
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Message 2 of 3

Re: router R6400 not connet with modem CM1200

Ok, I will try that. 

Message 3 of 3
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