Devices connected to extender cannot resolve domains besides google
Setup:
- TPLINK RE580D is connected via 2.4+5GHz bands to Xfinity router.
- Three devices (desktop, playstation4, raspberry pi) are connected to the extender via ethernet.
- All other devices on the network are connected to the xfinity router directly via wifi and have no problems.
- The three devices connected to the extender can also connect to the router directly and have no problems when doing so.
- This setup was working fine for months but recently I am having DNS issues wth the extender
Problem:
- The playstation and the desktop cant resolve any domain besides google and youtube. E.g., github does not work. SSH also does not work on the desktop (to or from device). Strangely enough, the raspberry fine works ok on all domains and SSH. The problem is the same whether it is connected to the extender via ethernet or the extender via WiFI. Again, no issues happen if any of these devices are connected directly to the router via ethernet or wifi. For the purpose of troubleshooting, I disabled the extender wifi network since I only need to connect to the extender via ethernet.
- The error logs of the extender are filled with "DNS probing failed. The DUT can not get a DNS server"
- There is also some "DHCP detection failed" in the error logs.
- It seems like my issue falls into Case #2 of this faq (https://www.tp-link.com/us/support/faq/2234/). It happens with multiple devices.
Troubleshooting:
- I'd prefer the three devices to have static IP (ie, the extender should not assign them new IPs). But for troubleshooting I made the DHCP on the extender enabled. I tried several common DNS IPs such as 8.8.8.8 and 8.8.4.4 as well as cloudflares, but this does not change anything.
- I tried rebooting the router via the web interface. Did nothing
- I tried rebooting the router via the power button and power cable, separately. Did nothing.
- I tried hard resetting the router with the RESET button. Did nothing
- I upgraded the firmware. Did nothing
- I spoke with the xfinity tech support for 3 hours and was escalated to their highest tier customer service (ie, directly to the backend engineers). They worked on trying to troubleshoot this for an entire day and determined nothing is wrong with the xfinity router (which is supported by the fact that all devices are fine when directly connected to the router). The problem must be with the extender.
- I checked all physical connections between the extender and the devices. They're all fine.
Any help is appreciated. Thanks