Problems updating your Asus router’s firmware? This might help!

Asus RT-AC66U router

A while ago, I ran into the following error message when I tried to update the firmware on my Asus RT-AC66U router.

Error message screenshot

The router cannot connect to ASUS server to check for the firmware update. After reconnecting to the Internet, go back to this page and click Check to check for the latest firmware updates.

It took me a while to figure out what was going on, so I thought I’d post it here in case anyone else runs into this.

The error message is pretty generic, but in my case it turned out to be caused by a faulty setting on the “WAN -> Internet Connection” screen.

WAN DNS settings screenshot

Apparently, I once set the DNS servers manually, then later removed the values, but forgot to set “Connect to DNS Server automatically” to “yes”.

It’s a little weird that Asus’s firmware accepts these settings, because without a DNS server, the router itself will not be able to access the internet properly. Clients will be fine if DNS servers are present in the LAN DHCP settings.

To fix this, either select “yes” to automatically connect to your ISP’s DNS servers, or specify your favorite servers.

Hope this helps.

Roy Tanck
I'm a freelance WordPress developer, designer, consultant, meetup organizer and speaker. In my spare time I love to go out and take pictures of things.