Can someone help me please? i have setup a little webserver on esp wich switches a relays like 192.168.2.221:84/relays-on or 192.168.2.221:84/relays-off. this works on a browser. Now there is another webserver running on an arduino uno with ethernet, this one must call the esp to switch relays on/off. HOW is the syntax for such a webcall please?
WiFi.hostname() only advertise its name to AP router during DHCP request. For any other purposes, you need to have mDNS service, and of course on Windows you need Bonjour, Linux already managing that using Avahi.