I have a mesh wireless system with outlying nodes that do not support an ethernet jack. To get around this, and avoiding hardwiring, I installed the commonly suggested TP Link Wifi Extender and connected my Antipodes server to it with an ethernet cable.
Over time I noticed some instability in my network and wifi bandwidth was diminished for my house. Also, the wireless speed through the extender was like 5Mbps, and I had issues with the occasional dropout. I started doing some testing, and one of the tests was to unplug the extender, voile, speed returned on the main network.
Doing some research and looking at configuration of the extender I discovered that DHCP was configured for the extender, making it a DHCP server as well as my router. Research stated to disable DHCP and set the IP for the extender to a fixed IP address on your main network.
Zing! Full speed on my network, 50Mbps on the extender.
These extenders are super handy, but as I discovered they can cause some problems if they are not configured correctly. Check yours if you are using one.