ESP8266 Community Forum

First eliminate dns from the test by using the ip address of the windows machine directly instead of its name.

That will tell you whether your problem is connectivity or name resolution.

I have already done so, I have tested the IP address directly and everything worked fine.

OK so the issue is not connection. It is name resolution, i.e. how to transform a name into an IP address.

Name resolution is a complex area as there are so many techniques used; e.g. DNS, host tables, multicastDNS, netBIOS, router based schemes.

Normal internet DNS doesn't work as the internet doesn't know your local machine names. You can set up a local DNS server which is then configured to know local names and also pass on other requests to the internet DNS.

host tables are just a local table of names to IP addresses that you have to separately maintain.

multicastDNS (mDNS) is a scheme to find hosts and / or services locally using a multicast packets which all devices hear and the one addressed by name responds to. mDNS library supports this on the ESP8266 both as a requester (searching of a host) and a responder (sending back IP address if requested). So you could use this method, but your other machines need to have a mDNS responder service running. I don't think this is the case for Windows machines unless you install it separately.

router based schemes can work if the router supports local DNS and you have set up static DHCP allocation to give hosts a fixed IP address and name. Not all routers can do this. I use a tomato router which does and it works well.