Failover fail when WAN plugged but disconneted to internet

My goal: having a system the switch on a secondary internet connection when the first fail.
I have installed and configured the system, tried-it unplugging the primary WAN....WOW all worked fine. After 10 days, due to work activities on optical fiber network, the primary WAN was go offline....and my system switch has failed to switching automatically on 4G line.
Solution? Suggestion?
PRIMARY WAN: Optical fiber with ONT to rj45
Connection Type: dynamic IP
Secondary WAN/LAN1: 4G_Backup on a real 4G_modem (no dongle)
Connection Type: dynamic IP
When Primary WAN is plugged and internet connected:
Internet is connected.
All LAN ports work perfectly:
When Primary WAN is Unplugged
The system in 30-45 seconds switch correctly on Secondary WAN
When Primary WAN is plugged and internet disconnected:
Internet is not connected.
The system not switch correctly on Secondary WAN
The wan status list show:
WAN online:
WAN/LAN Offline.
The load balancing is activated and also the online detection. I have followed all TPLink guide
The unique way to connect correctly to internet in this situation is push disconned to WAN button. After this, the system use the 4G modem.
- Copy Link
- Subscribe
- Bookmark
- Report Inappropriate Content
Hi @Paulum
Thanks for posting in our business forum.
Common Questions About the Load Balancing, Link Backup(Failover) & Online Detection
I have explained how it works for the online detection. Wirehshark and post your verification on if the primary WAN is no longer responding to the DNS resolution. If you have a video for that, that would be good.
- Copy Link
- Report Inappropriate Content
Thank you Clive for your reply. I have follow allo your forum suggestion and guide, but the problems is alreay here.
Today my Primary WAN work correctly but I need to resolve this issue of failover.
To test I have power off the ONT fiber converter to simulate a cutting of fiber (Primary WAN). The modem is power on, and all is plugged on ER605.
Same beahaviour of my first post. The system not switch on the secondary WAN (I have wait 5 minutes).
Attach
Part_1 (P1)
2 files for starting test:
WAN Primary OK
All Workig fine
Showing er605 status and tracert
Part_2 (P2)
ONT primary power off (simulation of WAN primary problems). All is plugged in ER605 and WAN Modem Power ON
1 File showing er605 status and tracert
The system after many minutes does not switch on the secondary WAN
- Copy Link
- Report Inappropriate Content
Hi @Paulum
Thanks for posting in our business forum.
Paulum wrote
Thank you Clive for your reply. I have follow allo your forum suggestion and guide, but the problems is alreay here.
Today my Primary WAN work correctly but I need to resolve this issue of failover.
To test I have power off the ONT fiber converter to simulate a cutting of fiber (Primary WAN). The modem is power on, and all is plugged on ER605.
Same beahaviour of my first post. The system not switch on the secondary WAN (I have wait 5 minutes).
Attach
Part_1 (P1)
2 files for starting test:
WAN Primary OK
All Workig fine
Showing er605 status and tracert
Part_2 (P2)
ONT primary power off (simulation of WAN primary problems). All is plugged in ER605 and WAN Modem Power ON
1 File showing er605 status and tracert
The system after many minutes does not switch on the secondary WAN
Set a public IP to the online detection on both WANs. Do not use Auto.
When you ping, are you able to ping the the IP you set for the detection?
It does not switch instantly. The standalone mode would take much longer than the controller mode.
- Copy Link
- Report Inappropriate Content
I have follow your istructions (manual IP). Same results of Auto.
Just a small difference:
A remark: using the internal ping test on diagnostics the ping response are good. Using the PC nothing.
I did the same test (diagnostics ping) with AUTO. The ping response are good. Using the PC nothing.
My LAN is configured using DHCP managed by ER605 (in attached the configuraton).
- Copy Link
- Report Inappropriate Content
Hi @Paulum
Thanks for posting in our business forum.
Paulum wrote
I have follow your istructions (manual IP). Same results of Auto.
Just a small difference:
A remark: using the internal ping test on diagnostics the ping response are good. Using the PC nothing.
I did the same test (diagnostics ping) with AUTO. The ping response are good. Using the PC nothing.
My LAN is configured using DHCP managed by ER605 (in attached the configuraton).
If the router can ping out the IPs or resolve the domains, it will consider the port as online regardless of your actual Internet accessibility.
This is the point I want you to test. If you say that the ping from the router can always go out and get a reply, then this is it.
Something is not okay on your modem router or ISP as the ping/resolution of the domain can be processed okay. This will make the router think the port is online and not to switch to the backup.
- Copy Link
- Report Inappropriate Content
Probably is not clear the situation in a failover real test.
WAN (primary) Plugged-in but internet disconneted
- the onboard ping diagnostic fail
WAN1/LAN (secondary) Plugged-in internet connected
- the onboard ping diagnostic working fine
- the ping using laptop connected to AP Ubiquiti fail
The status on ER 605 is:
WAN Online
WAN1/LAN Offline
Why?
I add an item related to my LAN. At the Er605 are connected some Standalone Ubiquiti AP that provide the WiFi connection. All the test using the laptop was realized using this WiFi connection. Do you have suggestion?
In the next days i will try the same test using cable LAN direct connected to ER 605.
- Copy Link
- Report Inappropriate Content
Hi @Paulum
Thanks for posting in our business forum.
Paulum wrote
Probably is not clear the situation in a failover real test.
WAN (primary) Plugged-in but internet disconneted- the onboard ping diagnostic fail
WAN1/LAN (secondary) Plugged-in internet connected- the onboard ping diagnostic working fine
- the ping using laptop connected to AP Ubiquiti fail
The status on ER 605 is:
WAN Online
WAN1/LAN Offline
Why?
I add an item related to my LAN. At the Er605 are connected some Standalone Ubiquiti AP that provide the WiFi connection. All the test using the laptop was realized using this WiFi connection. Do you have suggestion?
In the next days i will try the same test using cable LAN direct connected to ER 605.
The strange thing is that when it is actually "down", the router still displays WAN(primary) as online. Your video reflects the same thing. That's something I don't understand as well. But based on the mechanism I am explaining to you, that seems to be the problem, something resolves or allows the ping.
Like I said, the standalone mode does not switch instantly. It takes time.
And maybe something is not right with your environment which causes the router to mistakenly think the WAN is still alive.
If you try the controller mode, try setting the interval for the online detection to seconds.
With the stuff I have tried recently, last quarter, I have not seen a similar problem like this with ER7206 V2.
- Copy Link
- Report Inappropriate Content
I've re-checked the setup and test-it using standalone and controller. To avoid potentially wifi (ubiquiti) problems I have connect the laptop by cable directly on er605
Same problems both.
Standalone
WAN (primary) Plugged-in but internet disconneted
- the onboard ping diagnostic fail
WAN1/LAN (secondary) Plugged-in internet connected
- the onboard ping diagnostic fail (in the same previous test has working fine...)
- the ping using laptop fail
The only way to switch on secondary is: to unplug the cable of primary WAN
Using controller (on-line detection 1 minute, and wait to test more then 5 minutes)
WAN (primary) Plugged-in but internet disconneted
- the onboard ping diagnostic fail
WAN1/LAN (secondary) Plugged-in internet connected
- the onboard ping diagnostic fail
- the ping using laptop fail
Controller interface and log detect the primary connected and is impossible to go into internet.
The only way to switch on secondary is: to unplug the cable of primary WAN. When to do it, the system switch immediately on the secondary and come back on primary when replugged.
My opinion is that is a bug on the online detection (auto or manual) because always the devices are always routed on the wan even if this is really disconnected (but plugged in with modem power on). I will wait some days and the I will come back on standalone mode (I prefer) and if the failover will not resolve I will change the system and producer.
- Copy Link
- Report Inappropriate Content

Hi @Paulum
Thanks for posting in our business forum.
Paulum wrote
I've re-checked the setup and test-it using standalone and controller. To avoid potentially wifi (ubiquiti) problems I have connect the laptop by cable directly on er605
Same problems both.
Standalone
WAN (primary) Plugged-in but internet disconneted
- the onboard ping diagnostic fail
WAN1/LAN (secondary) Plugged-in internet connected- the onboard ping diagnostic fail (in the same previous test has working fine...)
- the ping using laptop fail
The only way to switch on secondary is: to unplug the cable of primary WAN
Using controller (on-line detection 1 minute, and wait to test more then 5 minutes)
WAN (primary) Plugged-in but internet disconneted
- the onboard ping diagnostic fail
WAN1/LAN (secondary) Plugged-in internet connected- the onboard ping diagnostic fail
- the ping using laptop fail
Controller interface and log detect the primary connected and is impossible to go into internet.
The only way to switch on secondary is: to unplug the cable of primary WAN. When to do it, the system switch immediately on the secondary and come back on primary when replugged.
My opinion is that is a bug on the online detection (auto or manual) because always the devices are always routed on the wan even if this is really disconnected (but plugged in with modem power on). I will wait some days and the I will come back on standalone mode (I prefer) and if the failover will not resolve I will change the system and producer.
Wireshark, and let's see how the router pings and receives the echo.
Or domains.
Use the KB article that I showed you how it works. That's how you break it down as well. Gotta see what the router receives to deem it is online.
- Copy Link
- Report Inappropriate Content

Information
Helpful: 0
Views: 169
Replies: 9
Voters 0
No one has voted for it yet.