Hello,

I have a TL-WA850RE v7 wifi extender and when I connect it to my main router (ASUS RT-AC1200), from that moment - if any device tries to register into the network through the main router, it does not have the internet access. The devices accessing the network through the extender work fine.

Initial situation

The main router is running a DHCP server and is responsible for assigning the IP adresses into the home network 192.168.1.X. It is also responsible for the wireless access to the home network througth the SSID called let's say HomeNetwork. There is also one other gateway in the house - the cable modem from the internet provider connected to the main router by the (main router's) WAN socket. The cable modem is running on a different network (192.168.0.x), has the wifi off and is connected to the main router by wire. So the main router has the IP address 192.168.0.10 given by the cable modem on the WAN interface and 192.168.1.1 in the home network. This setup has been running well for years. I just had a very weak signal of the HomeNetwork on the terrace, so wanted to boost it by a range extender.

Range extender installation

I have installed the range extender very easily, set-up a new SSID called HomeNetwork_EXT, left the extender it in the default (range extender) mode and turned the "DHCP Server" option to off (is Auto by default, so just to be sure). The extender connects easily to the main router, it even gets an IP address 192.168.1.200 from the main router (I guess just because of the config interface, otherwise the extender does not need the IP address). I connected the mobile phone from the terrace through the HomeNetwork_EXT and it worked well. I have turned on my laptop a couple of hours later inside the house, it tried to connect to the HomeNetwork, but it said "no internet". I have checked, but the phone connected to the HomeNetwork_EXT had the internet connection. The internet was working. This is where the problems started. I started testing the behaviour in different situations to pinpoint the cause. 

Tests

Test 1 - HomeNetwork_EXT always works

If I connect a new device to the network through HomeNetwork_EXT, the connected device works well - it can connect to the internet, sees the devices in the network etc. All good.

Test 2 - Turning off the extender immediately solves the problem

If I turn on my laptop and try to connect it to the HomeNetwork while the extender is on, the laptop says "no internet". The command ipconfig shows the laptop has the IP address assigned by the main router, but I cannot ping the main router (weirdly - like one out of 10 packages pings correctly, the others are lost immediately to "general error". not even a timeout). If I turn off the extender, the problem immediately disappears and the connection through HomeNetwork works perfectly again. ==> so I thought "hmm, it is somehow jamming HomeNetwork".

Test 3 - Wired devices connected to main router have the same issue

To confirm, I have tested this also with the wired devices. The extender is on. If the Smart TV had been turned on before the extender was turned on, it works well. However, if I make it get the new IP address from the main routers' DHCP server, it gets the new IP address, says all is fine, but Youtube/Netflix does not work because it just has no internet connection. If I turn the extender off, again, magically, the internet on the Smart TV starts working.

I have checked the logs in the main router, but there is no error logged, as if all was perfect.

I am running out of ideas what the cause could be. Anyone any thought?

Thank you very much