I've got a Linksys BEFW11S4 access point/4-port router that just started blinking the "DIAG" red led on the front panel. I can no longer connect through it. The net connection is ok since I can connect direct to the modem. I've tried powering it of and on to reboot, I've hit the reset button on the Linksys and nothing changes. I can't even connect to it with the browser by entering the local IP of 192.168.1.1

Is this puppy dead, or is there anything else to try?

Pretty much, yes. Contact Linksys support and as soon as they hear about the diag light staying on, they'll pretty much tell you it is shot. Then it becomes a matter of whether or not it is under warranty.

I was afraid of that. The led doesn't stay on steady, it just blinks continuously. Same verdict?

I'd think so. It doesn't cost anything to call Linksys. Give them a shot.

Hi,
I had this problem when i installed my old linksys router at a friends house.
The diag light was on. I called the cable provider and it was the mac address change from his equipment to my router that the cable broadband didnt understand.
They updated their details and i reset my router and it worked fine.
So call your broadband provider to check the MAC address is correct on their system.

Linksys tech support told me it's a dead indian. If the "Diag" led blinks continuously, it's a total hardware issue. Gave me a RMA number to send it in. Luckily I saved the receipt. The one year warranty runs out in 3 weeks.

Kewl beans, man.