RT-AC68U Says Internet Disconnected but can Still Access it Through VPN

[statman]

I started experiencing the following problem since I got fiber Internet installed in my home about a month ago: my new RT-AC68U randomly disconnects from the internet or at least pretends to. The log only shows the infamous "isp's dhcp did not function properly" message and on the main page of the webui, it shows "Internet Status: disconnected".

At this point, devices on the network can no longer access the Internet. However, if I click on the icon next to the Internet disconnected message, the interface still shows a wan IP, lists the dns servers and so on. Furthermore, if I use a VPN client on a computer connecting through the router, it is still able to connect and browse the Internet as usual. Also, I have a computer on the network which is connected through a VPN 24/7 and this one is not affected at all by this and can still connect to the Internet.

In order to restore the connection, I just need to go to the WAN page and click Apply, no need to change any setting. Connection is then restored within 10s.

I bought this router to replace a RT-AC66U because it exhibited the exact same behaviour. I upgraded to Merlin without success. As a matter of fact, disconnects are much more frequent since I started using Merlin. I have been working with my ISP on this but they did not find any problem. The modem is a Hitron CDA-RES which seems to be working fine. Its logs do not show any disconnect.

It might also be worth mentioning that the disconnections happen much more often when I run a backup program on my Synology NAS and the NAS is actively uploading files. At the same time, I have had friends able to connect from remote locations to my Plex server running on the NAS without any issue at the same moment when the router was saying it was disconnected from the Internet.

As everything seems to be working fine otherwise, I am under the impression that I am just missing a setting to adjust to solve the issue, but after testing many changes, I am running out of ideas and would appreciate any suggestion.

 

[Ed B.]

I know this post is from a while ago, however I encountered the same problem and figured out what the issue was and resolved it. I'm sure you've fixed the issue or ditched the router by now, so this is really for anyone else having the same issue that stumbles across this thread.

On my RT-AC3100, the internet was showing as 'Internet Disconnected', even though the internet was actually connected and working. Every now and then it would show as 'Internet Connected', but 95% of the time it said Disconnected.
The internet was actually connected very solidly, in fact I was VPNed into the router from the internet! Pinging direct IPs from the router worked (Network Tools->Network Analysis->Ping->8.8.8.8->Diagnose pinged at 15ms). NSLookups DID NOT work (Network Tools->Network Analysis->NSLookup->Google.com->Diagnose returned nothing).

The NSLookup issues helped me track the problem to my WAN DNS Addresses. I'm using OptOnline with a Static WAN IP and I had entered Google's 8.8.8.8 and 8.8.4.4 for the DNS Servers since I didn't see any reason that would be an issue. (I still don't see a reason why it would be an issue, especially since I could ping 8.8.8.8 from the router with no problem!)

Changing the WAN's DNS Servers to the OptOnline servers (167.206.112.138 and 167.206.7.4) fixed the issue. My WAN no longer shows 'Internet Disconnected' and instead shows 'Connected'.

I can't come up with any reason that using Google's 8.8.8.8 should cause an issue (short of accusing Optimum of nefarious behavior, but I just can't see that being the case). Anyhow, changing the WAN DNS Server addresses is an easy fix.

Of course if you're set up to get your WAN IP from your ISP via DHCP, then this is probably not going to help you (unless maybe you're not receiving/storing the DNS Server addresses). Either way, give NSLookup a shot to see if that's the issue.

Good Luck!

 

[BluesBrother]

I've run into this same problem with an ASUS RT-AC68U router connected to a standard Spectrum cable modem. I recently switched internet providers (from AT&T to Spectrum). Everything worked fine with AT&T. But when I connected my router to Spectrum's cable modem, everything works (including access to the internet for all my local devices) BUT the router's Network Map indicates that the the "Internet is Disconnected", even though the Internet Status appears normal (e.g., it's getting an WAN address via DHCP, it's getting two DNS addresses via DHCP, etc.). The OP doesn't indicate that he solved his problem, and Ed B. (above) suggests that in his case, the problem was the DNS addresses he was using (not my issue, because I'm using the DNS addresses returned by Spectrum). Any ideas?

 

[elmedico27]

I've run into this same problem with an ASUS RT-AC68U router connected to a standard Spectrum cable modem. I recently switched internet providers (from AT&T to Spectrum). Everything worked fine with AT&T. But when I connected my router to Spectrum's cable modem, everything works (including access to the internet for all my local devices) BUT the router's Network Map indicates that the the "Internet is Disconnected", even though the Internet Status appears normal (e.g., it's getting an WAN address via DHCP, it's getting two DNS addresses via DHCP, etc.). The OP doesn't indicate that he solved his problem, and Ed B. (above) suggests that in his case, the problem was the DNS addresses he was using (not my issue, because I'm using the DNS addresses returned by Spectrum). Any ideas?

I have the same but exactly opposite situation. My RT-AC1900P says "Internet status: Disconnected" even though everything works, however I'm currently on AT&T after moving from Spectrum (on which it showed connected). I believe it actually showed connected for a time even after the switch to AT&T Fiber. I'm using Cloudflare DNS currently and was on Spectrum as well. Haven't tried changing it yet, but I can give it a shot. It's weird, because it's not really a problem, but it still gives me that network admin eye twitch.

 

[elmedico27]

This post on another thread gave me the answer, and also fixed an issue I'd been having with the router not syncing to NTP. I switched from "ping" to "DNS query" and set the following options:

Resolve Hostname: www.cloudflare.com
Resolved IP Addresses: 104.17.210.9

NTP synced and my network map page now shows a status of connected. Huzzah!

 

[BluesBrother]

UPDATE... I think I finally figured out my problem with my RT-AC68U saying, "Internet Disconnected", even though it appeared to work fine as far as access from my local network devices (computers, e.g.). However, I could not check the status of the Firmware - it would always say, "Unable to contact ASUS..."

On a whim, I replaced the DNS addresses (normally obtained via DHCP from the ISP, Spectrum) with Google's DNS servers (8.8.8.8 and 8.8.4.4). And to my surprise (and puzzlement), voila! It worked! The Internet status went to, "connected". What the...?

So, from a browser, I attempted to contact ASUS (www.asus.com) using the Spectrum-supplied DNS addresses, and surprise, surprise: I got back a Spectrum "Terms of Service" page, requiring me to accept their conditions before proceeding. I did, then reverted to using the Spectrum-supplied DNS addresses on the router, rebooted the router, and everything worked fine - the Internet status now said, "Connected".

What I think was happening is that whenever the router attempted to contact ASUS using the Spectrum-supplied DNS addresses, Spectrum would intercept the request and return their Terms of Service page. Of course, a human would have been able to respond appropriately to that, but not a machine (the router). Consequently, not recognizing the response, the router threw up its hands and said, "Unable to contact ASUS...", and displayed, "Internet Disconnected". But once I discovered this and responded in the affirmative to their TOS page, the problem went away.

The reason I was still able to access the Internet from my local devices? I have my local devices configured with Google's DNS addresses (for speed and reliability), and so my computers (for instance) had no problem accessing the Internet, whereas the router was using the Spectrum-supplied addresses (until I temporarily overrode them using Google's addresses).

Boo on Spectrum for such a user/machine unfriendly setup!

 

[L&LD]

UPDATE... I think I finally figured out my problem with my RT-AC68U saying, "Internet Disconnected", even though it appeared to work fine as far as access from my local network devices (computers, e.g.). However, I could not check the status of the Firmware - it would always say, "Unable to contact ASUS..."

On a whim, I replaced the DNS addresses (normally obtained via DHCP from the ISP, Spectrum) with Google's DNS servers (8.8.8.8 and 8.8.4.4). And to my surprise (and puzzlement), voila! It worked! The Internet status went to, "connected". What the...?

So, from a browser, I attempted to contact ASUS (www.asus.com) using the Spectrum-supplied DNS addresses, and surprise, surprise: I got back a Spectrum "Terms of Service" page, requiring me to accept their conditions before proceeding. I did, then reverted to using the Spectrum-supplied DNS addresses on the router, rebooted the router, and everything worked fine - the Internet status now said, "Connected".

What I think was happening is that whenever the router attempted to contact ASUS using the Spectrum-supplied DNS addresses, Spectrum would intercept the request and return their Terms of Service page. Of course, a human would have been able to respond appropriately to that, but not a machine (the router). Consequently, not recognizing the response, the router threw up its hands and said, "Unable to contact ASUS...", and displayed, "Internet Disconnected". But once I discovered this and responded in the affirmative to their TOS page, the problem went away.

The reason I was still able to access the Internet from my local devices? I have my local devices configured with Google's DNS addresses (for speed and reliability), and so my computers (for instance) had no problem accessing the Internet, whereas the router was using the Spectrum-supplied addresses (until I temporarily overrode them using Google's addresses).

Boo on Spectrum for such a user/machine unfriendly setup!

Great detective work and a big thank you for sharing this with all.

 

[PRO006]

This post on another thread gave me the answer, and also fixed an issue I'd been having with the router not syncing to NTP. I switched from "ping" to "DNS query" and set the following options:

Resolve Hostname: www.cloudflare.com
Resolved IP Addresses: 104.17.210.9

NTP synced and my network map page now shows a status of connected. Huzzah!

Worked like a charm I've had this problem for months Cheers elmedico27

 

[lanman]

For me, I had overridden the DNS Server but I found that I typed the DNS Server1 wrong.