I have an RPi2B and an RPi3B. Both of them crash my router (ASUS AC68U) some time after wiring them to the network physically. After the router crash happened, all of my other devices (tablets, smartphones, PC's, some wired, some wifi) lose connection to the network. I can't even reach the configuration page of the router from my PC and ping to the router fails. The only way to get the network back is to unpower the router and switching it back on.

Some strange facts around this: 

* with a WiFi connection (for the RPi2B I have to use a WiFi dongle of course) the crash doesn't happen and everything works fine (forever)
* with a wired connection it works fine for like 10 minutes (so no DHCP problem I guess) until the crash happens
* it happens with Raspbian as well as LibreElec, so it isn't probably an OS problem

Because WiFi works, it doesn't hurt too much. But it leaves me with the feeling that I must have done something wrong.

Anyone got a similar problem and knows how to solve it?